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SRD5A2; steroid-5-alpha-reductase, alpha polypeptide 2 (3-oxo-5 alpha-steroid delta 4-dehydrogenase alpha 2) (2p23)

Gene Summary

Gene:SRD5A2; steroid-5-alpha-reductase, alpha polypeptide 2 (3-oxo-5 alpha-steroid delta 4-dehydrogenase alpha 2)
Location:2p23
Summary:This gene encodes a microsomal protein expressed at high levels in androgen-sensitive tissues such as the prostate. The encoded protein is active at acidic pH and is sensitive to the 4-azasteroid inhibitor finasteride. Deficiencies in this gene can result in male pseudohermaphroditism, specifically pseudovaginal perineoscrotal hypospadias (PPSH). [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, GeneCard, Gene
Protein:3-oxo-5-alpha-steroid 4-dehydrogenase 2
HPRD
Source:NCBI
Updated:25 November, 2014

Gene
Ontology:

What does this gene/protein do?
SRD5A2 is implicated in:
- 3-oxo-5-alpha-steroid 4-dehydrogenase activity
- androgen biosynthetic process
- androgen metabolic process
- cell differentiation
- cell-cell signaling
- endoplasmic reticulum membrane
- integral to membrane
- male gonad development
- progesterone 5-alpha-reductase activity
- small molecule metabolic process
- steroid metabolic process
- sterol 5-alpha reductase activity
Data from Gene Ontology via CGAP

Pathways:

What pathways are this gene/protein implicaed in?
- Androgen and estrogen metabolism KEGG
- Bile acid biosynthesis KEGG
Data from KEGG and BioCarta [BIOCARTA terms] via CGAP

Cancer Overview

The enzyme product of SRD5A2 is expressed in androgen-dependent tissues. It is responsible for converting testosterone to the more metabolically active dihydrotestosterone, which in turn transactivates a number of genes including prostate-specific antigen (PSA). There are a number of reports of polymorphisms and somatic mutations of SRD5A2 in prostate cancer. Polymorphisms of SRD5A2 have also been implicated in increased breast cancer risk (Bharaj, 2000).

Research Indicators

Publications Per Year (1989-2014)
Graph generated 25 November 2014 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • European Continental Ancestry Group
  • Sensitivity and Specificity
  • CYP17
  • Signal Transduction
  • Case-Control Studies
  • Chromosome 2
  • Sweden
  • Genetic Predisposition
  • Repetitive Sequences, Nucleic Acid
  • Transfection
  • Vitamin E
  • Polymerase Chain Reaction
  • Structure-Activity Relationship
  • Membrane Proteins
  • Prostatic Hyperplasia
  • Vitamin D
  • Trinucleotide Repeats
  • Prostate-Specific Antigen
  • Genotype
  • Receptors, Calcitriol
  • Taq Polymerase
  • Turkey
  • Tumor Markers
  • Cholestenone 5 alpha-Reductase
  • Odds Ratio
  • Risk Factors
  • Androgen Receptors
  • Genetic Variation
  • SRD5A2
  • Androgens
  • Testosterone
  • Polymorphism
  • Breast Cancer
  • Regression Analysis
  • Uterine Diseases
  • Alleles
  • Skin Diseases
  • 3-Oxo-5-alpha-Steroid 4-Dehydrogenase
  • Severity of Illness Index
  • Risk Assessment
  • Prostate Cancer
  • Treatment Failure
Tag cloud generated 25 November, 2014 using data from PubMed, MeSH and CancerIndex

Notable (2)

Entity Topic PubMed Papers
Prostate CancerSRD5A2 and Prostate Cancer View Publications118
Breast CancerSRD5A2 and Breast Cancer View Publications12

Related Links

Latest Publications: SRD5A2 (cancer-related)

Sang Q, Li X, Wang H, et al.
Quantitative methylation level of the EPHX1 promoter in peripheral blood DNA is associated with polycystic ovary syndrome.
PLoS One. 2014; 9(2):e88013 [PubMed] Free Access to Full Article Related Publications
Steroid synthesis and metabolic pathways play important roles in the pathophysiology of PCOS, but until now there have been no studies on the methylation profiles of specific genes in steroid synthesis pathways that are known to be associated with PCOS. Here we used MassARRAY quantitative methylation analysis to determine the methylation levels of each CpG site or cluster in the promoters of EPHX1, SRD5A1, and CYP11A1 in 64 peripheral blood samples. We further examined the methylation level of EPHX1 in an independent cohort consisting of 116 people. Finally, we investigated the role of EPHX1 in steroidogenesis in the KGN cell line. For SRD5A1 and CYP11A1, there was no significant difference in methylation level between patients and controls. For EPHX1, however, the methylation levels of a few consecutive CpG sites and clusters were found to be significantly associated with PCOS. The methylation levels of a number of CpG clusters or sites were significantly lower in patients than in controls in the first cohort consisting of 64 people, such as clusters 13-14 (P<0.05), 15-16 (P<0.001), and 19-24 (P<0.001) and sites CpG_53 (P<0.01) and CpG_54 (P<0.05). Among differentiated methylation sites and clusters, the methylation levels of the CpG cluster 13-14 and CpG cluster 19-24 in PCOS patients were significantly lower than in controls in the second cohort of 116 people (P<0.05 for both). In addition, knockdown and overexpression experiments in KGN cells showed that EPHX1 can regulate estradiol concentrations, and this indicates a role for EPHX1 in steroidogenesis. Our study has demonstrated that methylation of the EPHX1 promoter might be associated with PCOS. This study provides direct evidence that methylation plays an important role in PCOS and demonstrates a novel role for EPHX1 in female reproduction.


Lévesque É, Laverdière I, Lacombe L, et al.
Importance of 5α-reductase gene polymorphisms on circulating and intraprostatic androgens in prostate cancer.
Clin Cancer Res. 2014; 20(3):576-84 [PubMed] Related Publications
PURPOSE: Polymorphisms in the genes SRD5A1 and SRD5A2 encoding androgen biosynthetic 5α-reductase enzymes have been associated with an altered risk of biochemical recurrence after radical prostatectomy in localized prostate cancer.
EXPERIMENTAL DESIGN: To gain potential insights into SRD5A biologic effects, we examined the relationship between SRD5A prognostic markers and endogenous sex-steroid levels measured by mass spectrometry in plasma samples and corresponding prostatic tissues of patients with prostate cancer.
RESULTS: We report that five of the seven SRD5A markers differentially affect sex-steroid profiles of dihydrotestosterone and its metabolites in both the circulation and prostatic tissues of patients with prostate cancer. Remarkably, a 32% increase in intraprostatic testosterone levels was observed in the presence of the high-risk SRD5A rs2208532 polymorphism. Moreover, SRD5A2 markers were associated predominantly with circulating levels of inactive glucuronides. Indeed, the rs12470143 SRD5A2 protective allele was associated with high circulating androstane-3α, 17β-diol-17-glucuronide (3α-diol-17G) levels as opposed to lower levels of both 3α-diol-17G and androsterone-glucuronide observed with the rs2208532 SRD5A2 risk allele. Moreover, SRD5A2 rs676033 and rs523349 (V89L) risk variants, in strong linkage disequilibrium, were associated with higher circulating levels of 3α-diol-3G. The SRD5A2 rs676033 variant further correlated with enhanced intraprostatic exposure to 5α-reduced steroids (dihydrotestosterone and its metabolite 3β-diol). Similarly, the SRD5A1 rs166050C risk variant was associated with greater prostatic exposure to androsterone, whereas no association was noted with circulating steroids.
CONCLUSIONS: Our data support the association of 5α-reductase germline polymorphisms with the hormonal milieu in patients with prostate cancer. Further studies are needed to evaluate if these variants influence 5α-reductase inhibitor efficacy.

Related: Prostate Cancer


Jernberg E, Thysell E, Bovinder Ylitalo E, et al.
Characterization of prostate cancer bone metastases according to expression levels of steroidogenic enzymes and androgen receptor splice variants.
PLoS One. 2013; 8(11):e77407 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Intra-tumoral steroidogenesis and constitutive androgen receptor (AR) activity have been associated with castration-resistant prostate cancer (CRPC). This study aimed to examine if CRPC bone metastases expressed higher levels of steroid-converting enzymes than untreated bone metastases. Steroidogenic enzyme levels were also analyzed in relation to expression of constitutively active AR variants (AR-Vs) and to clinical and pathological variables.
METHODOLOGY/PRINCIPAL FINDINGS: Untreated, hormone-naïve (HN, n = 9) and CRPC bone metastases samples (n = 45) were obtained from 54 patients at metastasis surgery. Non-malignant and malignant prostate samples were acquired from 13 prostatectomy specimens. Transcript and protein levels were analyzed by real-time RT-PCR, immunohistochemistry and immunoblotting. No differences in steroidogenic enzyme levels were detected between CRPC and HN bone metastases. Significantly higher levels of SRD5A1, AKR1C2, AKR1C3, and HSD17B10 mRNA were however found in bone metastases than in non-malignant and/or malignant prostate tissue, while the CYP11A1, CYP17A1, HSD3B2, SRD5A2, and HSD17B6 mRNA levels in metastases were significantly lower. A sub-group of metastases expressed very high levels of AKR1C3, which was not due to gene amplification as examined by copy number variation assay. No association was found between AKR1C3 expression and nuclear AR staining, tumor cell proliferation or patient outcome after metastases surgery. With only one exception, high AR-V protein levels were found in bone metastases with low AKR1C3 levels, while metastases with high AKR1C3 levels primarily contained low AR-V levels, indicating distinct mechanisms behind castration-resistance in individual bone metastases.
CONCLUSIONS/SIGNIFICANCE: Induced capacity of converting adrenal-gland derived steroids into more potent androgens was indicated in a sub-group of PC bone metastases. This was not associated with CRPC but merely with the advanced stage of metastasis. Sub-groups of bone metastases could be identified according to their expression levels of AKR1C3 and AR-Vs, which might be of relevance for patient response to 2(nd) line androgen-deprivation therapy.

Related: Prostate Cancer


Titus MA, Li Y, Kozyreva OG, et al.
5α-reductase type 3 enzyme in benign and malignant prostate.
Prostate. 2014; 74(3):235-49 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Currently available 5α-reductase inhibitors are not completely effective for treatment of benign prostate enlargement, prevention of prostate cancer (CaP), or treatment of advanced castration-recurrent (CR) CaP. We tested the hypothesis that a novel 5α-reductase, 5α-reductase-3, contributes to residual androgen metabolism, especially in CR-CaP.
METHODS: A new protein with potential 5α-reducing activity was expressed in CHO-K1 cellsandTOP10 E. coli for characterization. Protein lysates and total mRNA were isolated from preclinical and clinical tissues. Androgen metabolism was assessed using androgen precursors and thin layer chromatography or liquid chromatography tandem mass spectrometry.
RESULTS: The relative mRNA expression for the three 5α-reductase enzymes in clinical samples of CR-CaP was 5α-reductase-3 ≫ 5α-reductase-1> 5α-reductase-2. Recombinant 5α-reductase-3 protein incubations converted testosterone, 4-androstene-3,17-dione (androstenedione) and 4-pregnene-3,20-dione (progesterone) to dihydrotestosterone, 5α-androstan-3,17-dione, and 5α-pregnan-3,20-dione, respectively. 5α-Reduced androgen metabolites were measurable in lysates from androgen-stimulated (AS) CWR22 and CR-CWR22 tumors and clinical specimens of AS-CaP and CR-CaP pre-incubated with dutasteride (a bi-specific inhibitor of 5α-reductase-1 and 2).
CONCLUSION: Human prostate tissues contain a third 5α-reductase that was inhibited poorly by dutasteride at high androgen substrate concentration in vitro, and it may promote DHT formation in vivo, through alternative androgen metabolism pathways when testosterone levels are low.

Related: Prostate Cancer


Ofude M, Mizokami A, Kumaki M, et al.
Repression of cell proliferation and androgen receptor activity in prostate cancer cells by 2'-hydroxyflavanone.
Anticancer Res. 2013; 33(10):4453-61 [PubMed] Related Publications
BACKGROUND: Prevention of the development of castration-resistant from hormone-naïve prostate cancer is an important issue in maintaining the quality of life of the patients. We explored the effect of 2'-hydroxyflavanone on proliferation and androgen responsiveness using prostate cancer cell lines.
MATERIALS AND METHODS: To investigate the effect of 2'-hydroxyflavanone on proliferation, prostate cancer cells were treated with 2'-hydroxyflavanone. Androgen-responsiveness in LNCaP cells was confirmed by luciferase assay after transfection of luciferase reporter driven by prostate specific antigen promoter. To detect androgen receptor (AR) expression, reverse transcriptase polymerase chain reaction and western blot analysis were conducted.
RESULTS: 2'-Hydroxyflavanone inhibited the proliferation of PC-3 and DU145 cells by induction of apoptosis. 2'-Hydroxyflavanone inhibited the proliferation of LNCaP cells stimulated by androgens and attenuated androgen-responsiveness through down-regulation of AR protein.
CONCLUSION: 2'-Hydroxyflavanone not only inhibited proliferation of prostate cancer cells, but also repressed androgen-responsiveness, suggesting that it might be a useful agent in preventing recurrence of prostate cancer.

Related: KLK3


Dowman JK, Hopkins LJ, Reynolds GM, et al.
Loss of 5α-reductase type 1 accelerates the development of hepatic steatosis but protects against hepatocellular carcinoma in male mice.
Endocrinology. 2013; 154(12):4536-47 [PubMed] Free Access to Full Article Related Publications
Nonalcoholic fatty liver disease (NAFLD) has been associated with glucocorticoid excess and androgen deficiency, yet in the majority of patients with steatohepatitis, circulating cortisol and androgen levels are normal. The enzyme 5α-reductase (5αR) has a critical role in androgen and glucocorticoid action. We hypothesize that 5αR has an important role in the pathogenesis of steatohepatitis through regulation of intracrine/paracrine hormone availability. Human liver samples from patients with NAFLD and normal donor tissue were used for gene expression and immunohistochemical analysis. NAFLD samples were scored using the Kleiner classification. In addition, 5αR1(-/-), 5αR2(-/-), and wild-type (WT) mice were fed normal chow or American lifestyle-induced obesity syndrome (ALIOS) diet for 6 or 12 months. Liver histology was graded and staged. Hepatic and circulating free fatty acid and triglyceride levels were quantified, and gene and protein expression was measured by real-time PCR and immunohistochemistry. 5αR1 and -2 were highly expressed in human liver, and 5αR1 protein expression increased with severity of NAFLD. 5αR1(-/-) (but not 5αR2(-/-)) mice fed an ALIOS diet developed greater hepatic steatosis than WT mice, and hepatic mRNA expression of genes involved in insulin signaling was decreased. Furthermore, 60% of WT mice developed focal hepatocellular lesions consistent with hepatocellular carcinoma after 12 months of the ALIOS diet, compared with 20% of 5αR2(-/-) and 0% of 5αR1(-/-) mice (P < .05). 5αR1 deletion accelerates the development of hepatic steatosis but may protect against the development of NAFLD-related hepatocellular neoplasia and therefore has potential as a therapeutic target.

Related: Liver Cancer


Arai S, Shibata Y, Nakamura Y, et al.
Development of prostate cancer in a patient with primary hypogonadism: intratumoural steroidogenesis in prostate cancer tissues.
Andrology. 2013; 1(1):169-74 [PubMed] Related Publications
Intratumoural steroidogenesis may play a significant role in the progression of prostate cancer (PC) in the context of long-term ablation of circulating testosterone (T). To clarify the mechanism accounting for the progression of PC in a 74-year-old man who had undergone bilateral orchiectomy when he was 5 years old, we performed immunohistochemical studies of androgen receptor (AR) and steroidogenic enzymes in the prostate. We also measured steroid hormone levels in the serum and prostate, as well as mRNA levels of genes mediating androgen metabolism in the prostate. Positive nuclear staining of AR was detected in malignant epithelial cells. The levels of androstenedione (Adione), T, and 5-alpha dihydrotestosterone (DHT) in the serum of the patient were similar to those in PC patients receiving neoadjuvant androgen deprivation therapy (ADT), but were higher in the patient's prostate than in PC patients not receiving ADT. The gene expression of CYP17A1 and HSD3B1 was not detected, whereas that of STS, HSD3B2, AKR1C3, SRD5A1, and SRD5A2 was detected. Moreover, cytoplasmic staining of HSD3B2, AKR1C3, SRD5A1, and SRD5A2 was detected in malignant epithelial cells. Hence, in the present case (a man with primary hypogonadism), steroidogenesis in PC tissues from adrenal androgens, especially dehydroepiandrosterone sulphate, was the mechanism accounting for progression of PC. This mechanism might help elucidate the development of castration-resistant PC.

Related: Prostate Cancer AR: androgen receptor


Sinreih M, Hevir N, Rižner TL
Altered expression of genes involved in progesterone biosynthesis, metabolism and action in endometrial cancer.
Chem Biol Interact. 2013; 202(1-3):210-7 [PubMed] Related Publications
Endometrial cancer (EC) is one of the most common gynecological malignancies worldwide. It is associated with prolonged exposure to estrogens that is unopposed by the protective effects of progesterone, which suggests that altered progesterone biosynthesis, metabolism and actions might be implicated in the development of EC. Our aim was to evaluate these processes through quantitative real-time PCR expression analysis in up to 47 pairs of EC tissue and adjacent control endometrium. First, we examined the expression of genes encoding proteins associated with progesterone biosynthesis: steroidogenic acute regulatory protein (STAR); a side chain cleavage enzyme (CYP11A1); and 3β-hydroxysteroid dehydrogenase/ketosteroid isomerase (HSD3B). There were 1.9- and 10.0-fold decreased expression of STAR and CYP11A1, respectively, in EC versus adjacent control endometrium, with no significant differences in the expression of HSD3B1 and HSD3B2. Next, we examined expression of genes encoding five progesterone metabolizing enzymes: the 3-keto and 20-ketosteroid reductases (AKR1C1-AKR1C3) and 5α-reductases (SRD5A1 and SRD5A2); and the opposing 20α-hydroxysteroid dehydrogenase (HSD17B2). These genes are expressed in EC and adjacent control endometrium. No statistically significant differences were seen in mRNA levels of AKR1C1, AKR1C2, AKR1C3 and SRD5A1. Expression of HSD17B2 was 3.0-fold increased, and expression of SRD5A2 was 3.7-fold decreased, in EC versus adjacent control endometrium. We also examined mRNA levels of progesterone receptors A and B (PGR), and separately the expression of progesterone receptor B (PR-B). Here we saw 1.8- and 2.0-fold lower mRNA levels of PGR and PR-B, respectively, in EC versus adjacent control endometrium. This down-regulation of STAR, CYP11A1 and PGR in endometrial cancer may lead to decreased progesterone biosynthesis and actions although the effects on progesterone levels should be further studied.

Related: Endometrial (Uterus) Cancer Endometrial Cancer


Lévesque É, Huang SP, Audet-Walsh É, et al.
Molecular markers in key steroidogenic pathways, circulating steroid levels, and prostate cancer progression.
Clin Cancer Res. 2013; 19(3):699-709 [PubMed] Related Publications
PURPOSE: Prostate cancer is a heterogeneous genetic disease, and molecular methods for predicting prognosis in patients with aggressive form of the disease are urgently needed to better personalize treatment approaches. The objective was to identify host genetic variations in candidate steroidogenic genes affecting hormone levels and prostate cancer progression.
EXPERIMENTAL DESIGN: The study examined two independent cohorts composed of 526 Caucasian men with organ-confined prostate cancer and 601 Taiwanese men on androgen-deprivation therapy. Caucasians were genotyped for 109 haplotype-tagging single-nucleotide polymorphisms (SNP) in CYP17A1, ESR1, CYP19A1, and HSD3B1, and their prognostic significance on disease progression was assessed using Kaplan-Meier survival curves and Cox regression models. Positive findings, including previously identified SRD5A1, SRD5A2, HSD17B2, HSD17B3, and HSD17B12 polymorphisms, were then explored in Taiwanese men (n = 32 SNPs). The influence of positive markers on the circulating hormonal levels was then appraised in Caucasians using specific and sensitive mass spectrometry-based methods.
RESULTS: After adjusting for known risk factors, variants of CYP17A1 (rs6162), HSD17B2 (rs4243229 and rs7201637), and ESR1 (rs1062577) were associated with progressive disease in both cohorts. Indeed, the presence of these variations was significantly associated with progression in Caucasians (HR, 2.29-4.10; P = 0.0014-2 × 10(-7)) and survival in Taiwanese patients [HR = 3.74; 95% confidence interval (CI): 1.71-8.19, P = 0.009]. Remarkably, the CYP17A1 rs6162 polymorphism was linked to plasma dehydroepiandrosterone-sulfate (DHEA-S) levels (P = 0.03), HSD17B2 rs7201637 with levels of dihydrotestosterone (P = 0.03), and ESR1 rs1062577 with levels of estrone-S and androsterone-glucuronide (P ≤ 0.05).
CONCLUSION: This study identifies, in different ethnic groups and at different disease stages, CYP17A1, HSD17B2, and ESR1 as attractive prognostic molecular markers of prostate cancer progression.

Related: Prostate Cancer Signal Transduction


Mitsiades N, Sung CC, Schultz N, et al.
Distinct patterns of dysregulated expression of enzymes involved in androgen synthesis and metabolism in metastatic prostate cancer tumors.
Cancer Res. 2012; 72(23):6142-52 [PubMed] Free Access to Full Article Related Publications
Androgen receptor (AR) signaling persists in castration-resistant prostate carcinomas (CRPC), because of several mechanisms that include increased AR expression and intratumoral androgen metabolism. We investigated the mechanisms underlying aberrant expression of transcripts involved in androgen metabolism in CRPC. We compared gene expression profiles and DNA copy number alteration (CNA) data from 29 normal prostate tissue samples, 127 primary prostate carcinomas (PCa), and 19 metastatic PCas. Steroidogenic enzyme transcripts were evaluated by quantitative reverse transcriptase PCR in PCa cell lines and circulating tumor cells (CTC) from CRPC patients. Metastatic PCas expressed higher transcript levels for AR and several steroidogenic enzymes, including SRD5A1, SRD5A3, and AKR1C3, whereas expression of SRD5A2, CYP3A4, CYP3A5, and CYP3A7 was decreased. This aberrant expression was rarely associated with CNAs. Instead, our data suggest distinct patterns of coordinated aberrant enzyme expression. Inhibition of AR activity by itself stimulated AKR1C3 expression. The aberrant expression of the steroidogenic enzyme transcripts was detected in CTCs from CRPC patients. In conclusion, our findings identify substantial interpatient heterogeneity and distinct patterns of dysregulated expression of enzymes involved in intratumoral androgen metabolism in PCa. These steroidogenic enzymes represent targets for complete suppression of systemic and intratumoral androgen levels, an objective that is supported by the clinical efficacy of the CYP17 inhibitor abiraterone. A comprehensive AR axis-targeting approach via simultaneous, frontline enzymatic blockade, and/or transcriptional repression of several steroidogenic enzymes, in combination with GnRH analogs and potent antiandrogens, would represent a powerful future strategy for PCa management.

Related: Prostate Cancer


Zambon CF, Prayer-Galetti T, Basso D, et al.
Effectiveness of the combined evaluation of KLK3 genetics and free-to-total prostate specific antigen ratio for prostate cancer diagnosis.
J Urol. 2012; 188(4):1124-30 [PubMed] Related Publications
PURPOSE: Of serum prostate specific antigen variability 40% depends on inherited factors. We ascertained whether the knowledge of KLK3 genetics would enhance prostate specific antigen diagnostic performance in patients with clinical suspicion of prostate cancer.
MATERIALS AND METHODS: We studied 1,058 men who consecutively underwent prostate biopsy for clinical suspicion of prostate cancer. At histology prostate cancer was present in 401 cases and absent in 657. Serum total prostate specific antigen and the free-to-total prostate specific antigen ratio were determined. Four polymorphisms of the KLK3 gene (rs2569733, rs2739448, rs925013 and rs2735839) and 1 polymorphism of the SRD5A2 gene (rs523349) were studied. The influence of genetics on prostate specific antigen variability was evaluated by multivariate linear regression analysis. The performance of total prostate specific antigen and the free-to-total prostate specific antigen ratio alone or combined with a genetically based patient classification were defined by ROC curve analyses.
RESULTS: For prostate cancer diagnosis the free-to-total prostate specific antigen ratio index alone (cutoff 11%) was superior to total prostate specific antigen (cutoff 4 ng/ml) and to free-to-total prostate specific antigen ratio reflex testing (positive predictive value 61%, 43% and 54%, respectively). Prostate specific antigen correlated with KLK3 genetics (rs2735839 polymorphism p = 0.001, and rs2569733, rs2739448 and rs925013 haplotype combination p = 0.003). In patients with different KLK3 genetics 2 optimal free-to-total prostate specific antigen ratio cutoffs (11% and 14.5%) were found. For free-to-total prostate specific antigen ratio values between 11% and 14.5% the prostate cancer probability ranged from 30.0% to 47.4% according to patient genetics.
CONCLUSIONS: The free-to-total prostate specific antigen ratio is superior to total prostate specific antigen for prostate cancer diagnosis, independent of total prostate specific antigen results. Free-to-total prostate specific antigen ratio findings below 11% are positively associated with prostate cancer and those above 14.5% are negatively associated with prostate cancer, while the interpretation of those between 11% and 14.5% is improved by patient KLK3 genetic analysis.

Related: Prostate Cancer KLK3


Kristiansen W, Aschim EL, Andersen JM, et al.
Variations in testosterone pathway genes and susceptibility to testicular cancer in Norwegian men.
Int J Androl. 2012; 35(6):819-27 [PubMed] Related Publications
Imbalance between the oestrogen and androgen levels in utero is hypothesized to influence testicular cancer (TC) risk. Thus, variation in genes involved in the action of sex hormones may contribute to variability of an individual's susceptibility to TC. Mutations in testosterone pathway genes may alter the level of testosterone in vivo and hypothetically the risk of developing TC. Luteinizing hormone receptor (LHR), 5α-reductase II (SRD5A2) and androgen receptor (AR) are key elements in androgen action. A case-control study comprising 651 TC cases and 313 controls in a Norwegian population was conducted for investigation of polymorphisms in the LHR, SRD5A and AR genes and their possible association with TC. A statistical significant difference was observed in patients being heterozygous for the LHR Asn312Ser polymorphism when comparing genotypes between all TC cases and controls (OR = 0.66, 95% CI = 0.48-0.89, p(adj) = 0.049). No statistically significant difference between the histological subtypes seminoma and non-seminoma was observed. Our results may suggest a possible association between genetic variation in the LHR gene and the risk of developing TC.

Related: Polymorphisms Testicular Cancer


Li J, Ding Z, Wang Z, et al.
Androgen regulation of 5α-reductase isoenzymes in prostate cancer: implications for prostate cancer prevention.
PLoS One. 2011; 6(12):e28840 [PubMed] Free Access to Full Article Related Publications
The enzyme 5α-reductase, which converts testosterone to dihydrotestosterone (DHT), performs key functions in the androgen receptor (AR) signaling pathway. The three isoenzymes of 5α-reductase identified to date are encoded by different genes: SRD5A1, SRD5A2, and SRD5A3. In this study, we investigated mechanisms underlying androgen regulation of 5α-reductase isoenzyme expression in human prostate cells. We found that androgen regulates the mRNA level of 5α-reductase isoenzymes in a cell type-specific manner, that such regulation occurs at the transcriptional level, and that AR is necessary for this regulation. In addition, our results suggest that AR is recruited to a negative androgen response element (nARE) on the promoter of SRD5A3 in vivo and directly binds to the nARE in vitro. The different expression levels of 5α-reductase isoenzymes may confer response or resistance to 5α-reductase inhibitors and thus may have importance in prostate cancer prevention.

Related: Dactinomycin Prostate Cancer AR: androgen receptor


Hein R, Abbas S, Seibold P, et al.
Polymorphism Thr160Thr in SRD5A1, involved in the progesterone metabolism, modifies postmenopausal breast cancer risk associated with menopausal hormone therapy.
Breast Cancer Res Treat. 2012; 131(2):653-61 [PubMed] Related Publications
Menopausal hormone therapy (MHT) is associated with an increased breast cancer risk in postmenopausal women, with combined estrogen-progestagen therapy posing a greater risk than estrogen monotherapy. However, few studies focused on potential effect modification of MHT-associated breast cancer risk by genetic polymorphisms in the progesterone metabolism. We assessed effect modification of MHT use by five coding single nucleotide polymorphisms (SNPs) in the progesterone metabolizing enzymes AKR1C3 (rs7741), AKR1C4 (rs3829125, rs17134592), and SRD5A1 (rs248793, rs3736316) using a two-center population-based case-control study from Germany with 2,502 postmenopausal breast cancer patients and 4,833 matched controls. An empirical-Bayes procedure that tests for interaction using a weighted combination of the prospective and the retrospective case-control estimators as well as standard prospective logistic regression were applied to assess multiplicative statistical interaction between polymorphisms and duration of MHT use with regard to breast cancer risk assuming a log-additive mode of inheritance. No genetic marginal effects were observed. Breast cancer risk associated with duration of combined therapy was significantly modified by SRD5A1_rs3736316, showing a reduced risk elevation in carriers of the minor allele (p (interaction,empirical-Bayes) = 0.006 using the empirical-Bayes method, p (interaction,logistic regression) = 0.013 using logistic regression). The risk associated with duration of use of monotherapy was increased by AKR1C3_rs7741 in minor allele carriers (p (interaction,empirical-Bayes) = 0.083, p (interaction,logistic regression) = 0.029) and decreased in minor allele carriers of two SNPs in AKR1C4 (rs3829125: p (interaction,empirical-Bayes) = 0.07, p (interaction,logistic regression) = 0.021; rs17134592: p (interaction,empirical-Bayes) = 0.101, p (interaction,logistic regression) = 0.038). After Bonferroni correction for multiple testing only SRD5A1_rs3736316 assessed using the empirical-Bayes method remained significant. Postmenopausal breast cancer risk associated with combined therapy may be modified by genetic variation in SRD5A1. Further well-powered studies are, however, required to replicate our finding.

Related: Breast Cancer


Audet-Walsh E, Bellemare J, Nadeau G, et al.
SRD5A polymorphisms and biochemical failure after radical prostatectomy.
Eur Urol. 2011; 60(6):1226-34 [PubMed] Related Publications
BACKGROUND: The relationship between inherited germ-line variations in the 5α-reductase pathways of androgen biosynthesis and the risk of biochemical recurrence (BCR) after radical prostatectomy (RP) remains an unexplored area.
OBJECTIVE: To determine the link between germ-line variations in the steroid-5α-reductase, α-polypeptide 1 (SRD5A1) and steroid-5α-reductase, α-polypeptide 2 (SRD5A2) genes and BCR.
DESIGN, SETTINGS, AND PARTICIPANTS: We studied retrospectively two independent cohorts composed of 526 white (25% BCR) and 320 Asian men (36% BCR) with pathologically organ-confined prostate cancer who had a median follow-up of 88.8 and 30.8 mo after surgery, respectively.
MEASUREMENTS: Patients were genotyped for 19 haplotype-tagging single nucleotide polymorphisms (htSNPs) in SRD5A1 and SRD5A2 genes, and their prognostic significance on prostate-specific antigen recurrence was assessed using Kaplan-Meier analysis and the Cox regression model.
RESULTS AND LIMITATIONS: After adjusting for all clinicopathologic risk factors, four SNPs (rs2208532, rs12470143, rs523349, and rs4952197) were associated with BCR in both whites and Asians. The strongest effect was conferred by the SRD5A2 V89L nonsynonymous SNP (rs523349C) with a hazard ratio (HR) of 2.87 (95% confidence interval [CI], 2.07-4.00; p = 4 × 10⁻¹⁰; 48% BCR). In addition, in whites, the combination of two SNPs, rs518673T in SRD5A1 and rs12470143A in SRD5A2, was associated with a reduced BCR rate for carriers of three or four alleles (HR: 0.37; 95% CI, 0.19-0.71; p=0.003;16% BCR) compared with noncarriers (38% BCR), whereas the SRD5A2 rs12470143A was significant in Asians (HR: 0.46; 95% CI, 0.28-0.73; p=0.001). Limitations of our study include few events of androgen-deprivation resistance or cancer-specific death.
CONCLUSIONS: Our study is the first to show positive associations of several SRD5A1 and SRD5A2 variations as independent predictors of BCR after RP.

Related: Prostate Cancer


Izmirli M, Arikan B, Bayazit Y, Alptekin D
Associations of polymorphisms in HPC2/ELAC2 and SRD5A2 genes with benign prostate hyperplasia in Turkish men.
Asian Pac J Cancer Prev. 2011; 12(3):731-3 [PubMed] Related Publications
Benign prostate hyperplasia (BPH) is the most common benign tumor in elderly men for which the HPC2/ELAC2 and SRD5A2 genes are known genetic factors. The HPC2/ELAC2 gene features Ser217Leu and Ala541Thr polymorphisms and the SRD5A2 gene Ala49Thr and Val89Leu polymorphisms. The aim of this study was to examine relationships between these polymorphisms and BPH in Turkish men using amplification by the polymerase chain reaction (PCR) method. Polymorphisms were determined by using restriction fragment length polymorphism (RFLP) with suitable restriction: TaqI?, Fnu4HI, Mwo I and Rsa I. We found statistically significant relationship between the SRD5A2 gene Ala49Thr (OR=2.3; CI 95%, 1.04-5.1; p=0.01<0.05) , but not the other polymorphisms, and BPH. For the first time, our data demonstrate that the correlation between SRD5A2 gene Ala49Thr and polymorphisms is statistically significant in Turkish men with BPH.

Related: Polymorphisms Prostate Cancer


Barnholtz-Sloan JS, Guan X, Zeigler-Johnson C, et al.
Decision tree-based modeling of androgen pathway genes and prostate cancer risk.
Cancer Epidemiol Biomarkers Prev. 2011; 20(6):1146-55 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Inherited variability in genes that influence androgen metabolism has been associated with risk of prostate cancer. The objective of this analysis was to evaluate interactions for prostate cancer risk by using classification and regression tree (CART) models (i.e., decision trees), and to evaluate whether these interactive effects add information about prostate cancer risk prediction beyond that of "traditional" risk factors.
METHODS: We compared CART models with traditional logistic regression (LR) models for associations of factors with prostate cancer risk using 1,084 prostate cancer cases and 941 controls. All analyses were stratified by race. We used unconditional LR to complement and compare with the race-stratified CART results using the area under curve (AUC) for the receiver operating characteristic curves.
RESULTS: The CART modeling of prostate cancer risk showed different interaction profiles by race. For European Americans, interactions among CYP3A43 genotype, history of benign prostate hypertrophy, family history of prostate cancer, and age at consent revealed a distinct hierarchy of gene-environment and gene-gene interactions, whereas for African Americans, interactions among family history of prostate cancer, individual proportion of European ancestry, number of GGC androgen receptor repeats, and CYP3A4/CYP3A5 haplotype revealed distinct interaction effects from those found in European Americans. For European Americans, the CART model had the highest AUC whereas for African Americans, the LR model with the CART discovered factors had the largest AUC.
CONCLUSION AND IMPACT: These results provide new insight into underlying prostate cancer biology for European Americans and African Americans.

Related: Prostate Cancer AR: androgen receptor


Balistreri CR, Caruso C, Carruba G, et al.
Genotyping of sex hormone-related pathways in benign and malignant human prostate tissues: data of a preliminary study.
OMICS. 2011; 15(6):369-74 [PubMed] Related Publications
Prostate cancer (PCa) is a major health issue in Westernized countries, representing a common cause of morbidity and mortality in the elderly male population. Endogenous sex steroids, along with environmental factors (notably diet) and host immune and inflammatory responses, are likely to cooperate in the pathogenesis of the disease. Based on the assumption that a complex endocrine-inflammatory-immune interaction is primarily implicated in human PCa, we have investigated the interplay between sex steroids and inflammation in development and growth of human PCa. To this end, we have assessed nine functional single nucleotide polymorphisms (SNP)s of five genes involved in sex hormone-related pathways in both hyperplastic and malignant human prostate tissues, as well as in matched controls and in a "supercontrol" group composed of male Sicilian centenarians. In particular, the following genes were investigated: AR-OMIM313700, SRD5A2-NM-000348, CYP19-NM-031226, ERS1-NM-001122742, ERS2-NM-001040276. A significant association with PCa was found in seven out of the nine SNPs considered. Although this is a preliminary study and larger investigations are needed to confirm the role of these genes in PCa development and/or progression, our data might provide an experimental basis to develop additional or alternative strategies for prevention and treatment of PCa.

Related: Prostate Cancer


Li X, Huang Y, Fu X, et al.
Meta-analysis of three polymorphisms in the steroid-5-alpha-reductase, alpha polypeptide 2 gene (SRD5A2) and risk of prostate cancer.
Mutagenesis. 2011; 26(3):371-83 [PubMed] Related Publications
The steroid-5-alpha-reductase, alpha polypeptide 2 (SRD5A2) gene plays a crucial role in androgen metabolism pathway in human prostate. It encodes SRD5A2 enzyme, which catalyses testosterone to dihydrotestosterone (DHT). DHT is the main active structure binding with androgen receptor (AR). After the activation of AR, it further regulates a series of target genes in androgen metabolism pathway. However, no clear consensus has been reached on the association between the SRD5A2 V89L, A49T and TA repeat polymorphisms and prostate cancer (PCa) risk. Thus, we performed a meta-analysis of 31 association studies with 14,726 PCa cases and 15,802 controls. We found no association between PCa and 89L compared with 89V allele [odds ratio (OR) = 1.02, 95% confidence interval (CI) 0.98-1.06, P(heterogeneity) = 0.44]. The 49T allele showed a significantly elevated effect on the high stage (Stages III-IV) of PCa risk both under the dominant genetic model (OR = 2.13, 95% CI 1.44-3.15, P(heterogeneity) = 0.65) and in the contrast T versus A allele (OR = 2.06, 95% CI 1.41-3.02, P(heterogeneity) = 0.69). There was a significantly decreased association between PCa and long TA repeat as compared versus short TA repeat (OR = 0.86, 95% CI 0.74-1.00, P(heterogeneity) = 0.79). No significant between-study heterogeneity was found in all subjects under four genetic models (dominant model, recessive model, allele comparison and homozygosity comparison) for these three polymorphisms, respectively, so the fixed effects model was used to pool the result. Our result indicated that carriers of 49T might improve the risk of PCa in higher stages (Stages III-IV), carriers of long TA repeat might decrease the risk of PCa and 89L may not be an important risk factor for PCa. However, due to the limited sample sizes, this meta-analysis did not achieve sufficiently conclusive results. Still more well-designed studies should be performed to clarify the role of these three polymorphisms in the development of PCa.

Related: Polymorphisms Prostate Cancer


Hulin-Curtis SL, Petit D, Figg WD, et al.
Finasteride metabolism and pharmacogenetics: new approaches to personalized prevention of prostate cancer.
Future Oncol. 2010; 6(12):1897-913 [PubMed] Related Publications
Incidences of prostate cancer in most countries are increasing owing to better detection methods; however, prevention with the use of finasteride, a very effective steroid 5α-reductase type II inhibitor, has been met with mixed success. A wide interindividual variation in response exists and is thought to be due to heritable factors. This article summarizes the literature that attempts to elucidate the molecular mechanisms of finasteride in terms of its metabolism, excretion and interaction with endogenous steroid molecules. We describe previously reported genetic variations of steroid-metabolizing genes and their potential association with finasteride efficacy. Based on the literature, we outline directions of research that may contribute to understanding the interindividual variation in finasteride prevention and to the future development of personalized medicine.

Related: Prostate Cancer


Samtani R, Bajpai M, Ghosh PK, Saraswathy KN
SRD5A2 gene mutations--a population-based review.
Pediatr Endocrinol Rev. 2010; 8(1):34-40 [PubMed] Related Publications
Knowledge of steroid 5 alpha-reductase type 2 (SRD5A2) gene mutations is expanding, and its role has been implicated in various disease susceptibilities concerning reproductive health. Extensive research has revealed the tendency for specific SRD5A2 gene mutations to be passed along certain racial, ethnic and geographically isolated groups, which suggests population specificity of these mutations. The review provides evidence of variation in the mutational spectrum of the SRD5A2 gene leading to population-specific high prevalence of characteristic disease or phenotypic expression.

Related: Prostate Cancer


Iizuka N, Oka M, Sakaida I, et al.
Efficient detection of hepatocellular carcinoma by a hybrid blood test of epigenetic and classical protein markers.
Clin Chim Acta. 2011; 412(1-2):152-8 [PubMed] Related Publications
BACKGROUND: There are few blood tests for an efficient detection of hepatocellular carcinoma (HCC) associated with hepatitis C virus (HCV) infection.
METHODS: The abilities of quantitative analyses of 7 genes hypermethylation in serum DNA, α-fetoprotein (AFP) and prothrombin-induced vitamin K absence II (PIVKA-II), and various combinations to detect HCC were evaluated in a training cohort of 164 HCV-infected patients (108 HCCs; 56 non-HCCs). An optimal hybrid detector, built using data for 2 methylated genes (SPINT2 and SRD5A2), AFP, and PIVKA-II, achieved the most satisfactory ability to detect HCC in the training cohort. We evaluated the ability of the optimal hybrid detector to detect HCC in an independent validation cohort of 258 consecutive HCV-infected patients (112 HCCs; 146 non-HCCs) who were newly enrolled in 4 distinct institutes.
RESULTS: In the validation cohort of 258 patients, accuracy, sensitivity, and specificity of the hybrid detector for detection of HCC were 81.4%, 73.2%, and 87.7%, respectively. Notably, even when detecting HCC ≤ 2 cm in diameter, the hybrid detector maintained markedly high abilities (84.6% accuracy, 72.2% sensitivity, 87.7% specificity). Youden's index (sensitivity+specificity - 1) for HCC ≤ 2cm was 0.60, vastly much superior to the 0.39 for AFP at a cut-off value of 20 ng/ml and the 0.28 for PIVKA-II at a cut-off value of 40 mAU/ml.
CONCLUSIONS: These results show that the optimal hybrid blood detector can detect HCV-related HCC more accurately.

Related: Liver Cancer


Uemura M, Honma S, Chung S, et al.
5alphaDH-DOC (5alpha-dihydro-deoxycorticosterone) activates androgen receptor in castration-resistant prostate cancer.
Cancer Sci. 2010; 101(8):1897-904 [PubMed] Related Publications
Prostate cancer often relapses during androgen-depletion therapy, even under the castration condition in which circulating androgens are drastically reduced. High expressions of androgen receptor (AR) and genes involved in androgen metabolism indicate a continued role for AR in castration-resistant prostate cancers (CRPCs). There is increasing evidence that some amounts of 5alpha-dihydrotestosterone (DHT) and other androgens are present sufficiently to activate AR within CRPC tissues, and enzymes involved in the androgen and steroid metabolism, such as 5alpha-steroid reductases, are activated in CRPCs. In this report, we screened eight natural 5alphaDH-steroids to search for novel products of 5alpha-steroid reductases, and identified 11-deoxycorticosterone (DOC) as a novel substrate for 5alpha-steroid reductases in CRPCs. 11-Deoxycorticosterone (DOC) and 5alpha-dihydro-deoxycorticosterone (5alphaDH-DOC) could promote prostate cancer cell proliferation through AR activation, and type 1 5alpha-steroid reductase (SRD5A1) could convert from DOC to 5alphaDH-DOC. Sensitive liquid chromatography-tandem mass spectrometric analysis detected 5alphaDH-DOC in some clinical CRPC tissues. These findings implicated that under an extremely low level of DHT, 5alphaDH-DOC and other products of 5alpha-steroid reductases within CRPC tissues might activate the AR pathway for prostate cancer cell proliferation and survival under castration.

Related: Prostate Cancer


Das K, Lorena PD, Ng LK, et al.
Differential expression of steroid 5alpha-reductase isozymes and association with disease severity and angiogenic genes predict their biological role in prostate cancer.
Endocr Relat Cancer. 2010; 17(3):757-70 [PubMed] Related Publications
The biological role of steroid 5alpha-reductase isozymes (encoded by the SRD5A1 and SRD5A2 genes) and angiogenic factors that play important roles in the pathogenesis and vascularization of prostate cancer (PC) is poorly understood. The sub-cellular expression of these isozymes and vascular endothelial growth factor (VEGF) in PC tissue microarrays (n=62) was examined using immunohistochemistry. The effect of SRD5A inhibition on the angiogenesis pathway genes in PC was also examined in prostate cell lines, LNCaP, PC3, and RWPE-1, by treating them with the SRD5A inhibitors finasteride and dutasteride, followed by western blot, quantitative PCR, and ELISA chip array techniques. In PC tissues, nuclear SRD5A1 expression was strongly associated with higher cancer Gleason scores (P=0.02), higher cancer stage (P=0.01), and higher serum prostate specific antigen (PSA) levels (P=0.01), whereas nuclear SRD5A2 expression was correlated with VEGF expression (P=0.01). Prostate tumor cell viability was significantly reduced in dutasteride-treated PC3 and RWPE-1 cells compared with finasteride-treated groups. Expression of the angiogenesis pathway genes transforming growth factor beta 1 (TGFB1), endothelin (EDN1), TGFalpha (TGFA), and VEGFR1 was upregulated in LNCaP cells, and at least 7 out of 21 genes were upregulated in PC3 cells treated with finasteride (25 muM). Our findings suggest that SRD5A1 expression predominates in advanced PC, and that inhibition of SRD5A1 and SRD5A2 together was more effective in reducing cell numbers than inhibition of SRD5A2 alone. However, these inhibitors did not show any significant difference in prostate cell angiogenic response. Interestingly, some angiogenic genes remained activated after treatment, possibly due to the duration of treatment and tumor resistance to inhibitors.

Related: Prostate Cancer VEGFA AR: androgen receptor


Ashton KA, Proietto A, Otton G, et al.
Polymorphisms in genes of the steroid hormone biosynthesis and metabolism pathways and endometrial cancer risk.
Cancer Epidemiol. 2010; 34(3):328-37 [PubMed] Related Publications
OBJECTIVES: The incidence of endometrial cancer has recently increased substantially and studies have shown that altered levels of exogenous and endogenous hormones are associated with individual variation in endometrial cancer risk. The environmental and reproductive risk factors that influence these hormones are well known, however, genetic variants involved in hormone biosynthesis and estrogen metabolism have not been well established in endometrial cancer.
METHODS: To determine whether polymorphisms in genes of the steroid hormone biosynthesis and metabolism pathways are associated with endometrial cancer risk, 28 polymorphisms in 18 genes were genotyped in 191 endometrial cancer cases and 291 healthy controls.
RESULTS: The GSTM1 deletion and the variant (GG) genotype of the CYP1B1 rs1800440 polymorphism were associated with a decreased risk of developing endometrial cancer. Furthermore, combinations of haplotypes in CYP1A1, CYP1B1 and GSTs were associated with a decreased risk. The analysis of the repeat polymorphisms revealed that women with the long repeat allele length of the ESR1 (GT)n repeat polymorphism were at an increased risk of developing endometrial cancer. Conversely, women with two long repeat length alleles of the (CAG)n repeat polymorphism in the AR correlated with a decrease in endometrial cancer risk compared to women with one or two alleles with the short repeat length.
CONCLUSIONS: The findings are consistent with our hypothesis that variability in genes involved in steroidogenesis and estrogen metabolism may alter the risk of developing endometrial cancer, suggesting that they may be useful as biomarkers for genetic susceptibility to endometrial cancer.

Related: Endometrial (Uterus) Cancer Endometrial Cancer Polymorphisms ESR1


Hofland J, van Weerden WM, Dits NF, et al.
Evidence of limited contributions for intratumoral steroidogenesis in prostate cancer.
Cancer Res. 2010; 70(3):1256-64 [PubMed] Related Publications
Androgen-deprivation therapy for prostate cancer (PC) eventually leads to castration-resistant PC (CRPC). Intratumoral androgen production might contribute to tumor progression despite suppressed serum androgen concentrations. In the present study, we investigated whether PC or CRPC tissue may be capable of intratumoral androgen synthesis. Steroidogenic enzyme mRNAs were quantified in hormonally manipulated human PC cell lines and xenografts as well as in human samples of normal prostate, locally confined and advanced PC, local nonmetastatic CRPC, and lymph node metastases. Overall, the majority of samples showed low or absent mRNA expression of steroidogenic enzymes required for de novo steroid synthesis. Simultaneous but low expression of the enzymes CYP17A1 and HSD3B1, essential for the synthesis of androgens from pregnenolone, could be detected in 19 of 88 patient samples. Of 19 CRPC tissues examined, only 5 samples expressed both enzymes. Enzymes that convert androstenedione to testosterone (AKR1C3) and testosterone to dihydrotestosterone (DHT; SRD5A1) were abundantly expressed. AKR1C3 expression was negatively regulated by androgens in the experimental models and was increased in CRPC samples. Expression of SRD5A1 was upregulated in locally advanced cancer, CRPC, and lymph node metastases. We concluded that intratumoral steroid biosynthesis contributes less than circulating adrenal androgens, implying that blocking androgen production and its intraprostatic conversion into DHT, such as via CYP17A1 inhibition, may represent favorable therapeutic options in patients with CRPC.

Related: Prostate Cancer CYP17A1


Setlur SR, Chen CX, Hossain RR, et al.
Genetic variation of genes involved in dihydrotestosterone metabolism and the risk of prostate cancer.
Cancer Epidemiol Biomarkers Prev. 2010; 19(1):229-39 [PubMed] Related Publications
PURPOSE: Dihydrotestosterone (DHT) is an important factor in prostate cancer (PCA) genesis and disease progression. Given PCA's strong genetic component, we evaluated the possibility that variation in genes involved in DHT metabolism influence PCA risk.
EXPERIMENTAL DESIGN: We investigated copy number variants (CNV) and single nucleotide polymorphisms (SNP). We explored associations between CNV of uridine diphospho-glucuronosyltransferase (UGT) genes from the 2B subclass, given their prostate specificity and/or involvement in steroid metabolism and PCA risk. We also investigated associations between SNPs in genes (HSD3B1, SRD5A1/2, and AKR1C2) involved in the conversion of testosterone to DHT, and in DHT metabolism and PCA risk. The population consisted of 426 men (205 controls and 221 cases) who underwent prostate-specific antigen screening as part of a PCA early detection program in Tyrol, Austria.
RESULTS: No association between CNV in UGT2B17 and UGT2B28 and PCA risk was identified. Men carrying the AA genotype at SNP rs6428830 (HSD3B1) had an odds ratio (OR) of 2.0 [95% confidence intervals (95% CI), 1.1-4.1] compared with men with GG, and men with AG or GG versus AA in rs1691053 (SRD5A1) had an OR of 1.8 (95% CI, 1.04-3.13). Individuals carrying both risk alleles had an OR of 3.1 (95% CI, 1.4-6.7) when compared with men carrying neither (P = 0.005). Controls with the AA genotype on rs7594951 (SRD5A2) tended toward higher serum DHT levels (P = 0.03).
CONCLUSIONS: This is the first study to implicate the 5alpha-reductase isoform 1 (SRD5A1) and PCA risk, supporting the rationale of blocking enzymatic activity of both isoforms of 5alpha-reductase for PCA chemoprevention.

Related: Prostate Cancer


Tsunedomi R, Ogawa Y, Iizuka N, et al.
The assessment of methylated BASP1 and SRD5A2 levels in the detection of early hepatocellular carcinoma.
Int J Oncol. 2010; 36(1):205-12 [PubMed] Related Publications
We previously identified BASP1 and SRD5A2 as novel hepatocellular carcinoma (HCC) methylation markers from among more than 10,000 screened genes. The present study aimed to improve the diagnostic potential of these genes. We compared the methylation status at distinct regions of the BASP1 and SRD5A2 genes using quantitative methylation-specific PCR, in 46 sets of HCC and corresponding non-tumor liver tissues. We also examined how their epigenetic status affected transcript levels in tissues and several hepatoma cell lines. We found that BASP1 and SRD5A2 loci were methylated in greater than 50% of the HCC tissues. Inverse correlations were identified between the methylation status and transcript levels in the tissues. Assessment of CpG island methylation rate of BASP1 and SRD5A2 resulted in different diagnostic powers for discriminating HCC even in the same CpG island. A combination analysis of BASP1 and SRD5A2 resulted in the optimum diagnostic performance (84.8% sensitivity and 91.3% specificity) with a maximal area under the receiver operating characteristic curve of 0.878. Even in patients with early HCC (well-differentiated, TNM stage I and small in diameter) and those negative for serum alpha-fetoprotein, combination analysis enabled an accurate diagnosis of HCC. In vitro analysis also showed that BASP1 and SRD5A2 transcripts were epigenetically regulated by methylation and acetylation. These results suggest that combined analysis of methylated BASP1 and SRD5A2 may prove useful in the accurate diagnosis of HCC, especially early HCC.

Related: Liver Cancer


Li J, Coates RJ, Gwinn M, Khoury MJ
Steroid 5-{alpha}-reductase Type 2 (SRD5a2) gene polymorphisms and risk of prostate cancer: a HuGE review.
Am J Epidemiol. 2010; 171(1):1-13 [PubMed] Related Publications
Steroid 5-alpha-reductase type 2 (SRD5a2) is a critical enzyme in androgen metabolism. Two polymorphisms in the SRD5a2 gene, V89L (rs523349) and A49T (rs9282858), have been studied for associations with prostate cancer risk, with conflicting results. The authors conducted a systematic review and meta-analysis (1997-2007) to examine these associations and compared the results with findings from genome-wide association studies of prostate cancer. The meta-analysis included 24 case-control studies (10,088 cases and 10,120 controls for V89L and 4,998 cases and 5,451 controls for A49T). The authors found that prostate cancer was not associated with V89L (L allele vs. V allele: odds ratio = 0.99, 95% confidence interval: 0.94, 1.05) and was probably not associated with A49T (T allele vs. A allele: odds ratio = 1.10, 95% confidence interval: 0.86, 1.40). These results could have been distorted by spectrum-of-disease bias, convenience sampling of cases and controls, genotype misclassification, and/or confounding. Neither V89L nor A49T was included in microarray chips used for published genome-wide association studies. Analysis of well-designed population-based studies with pathway-based arrays containing common genetic variants could be useful for identifying genetic factors in prostate cancer.

Related: Polymorphisms Prostate Cancer


Reding KW, Li CI, Weiss NS, et al.
Genetic variation in the progesterone receptor and metabolism pathways and hormone therapy in relation to breast cancer risk.
Am J Epidemiol. 2009; 170(10):1241-9 [PubMed] Free Access to Full Article Related Publications
The relevance of progesterone to breast carcinogenesis is highlighted by evidence indicating that use of combined estrogen-progesterone therapy (EPT) is more strongly related to breast cancer risk than is use of unopposed estrogen therapy. However, few investigators have assessed how genetic variation in progesterone-related genes modifies the effect of EPT on risk. In an analysis combining data from 2 population-based case-control studies of postmenopausal breast cancer (1,296 cases and 1,055 controls) conducted in Washington State in 1997-1999 and 2000-2004, the authors evaluated how 51 single nucleotide polymorphisms in 7 progesterone-related genes (AKR1C1, AKR1C2, AKR1C3, CYP3A4, SRD5A1, SRD5A2, and PGR) influenced breast cancer risk. There was no appreciable association with breast cancer risk overall for any single nucleotide polymorphism. For rs2854482 in AKR1C2, carrying 1 or 2 A alleles was associated with a 2.0-fold increased breast cancer risk in EPT users (95% confidence interval: 1.0, 4.0) but not in never users (P(heterogeneity) = 0.03). For rs12387 in AKR1C3, the presence of 1 or 2 G alleles was associated with a 1.5-fold increased risk among EPT users (95% confidence interval: 1.1, 2.2) but not in never users (P(heterogeneity) = 0.02). Interpretation of these subgroup associations must await the results of similar studies conducted in other populations.

Related: Breast Cancer


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