CYP19A1

Gene Summary

Gene:CYP19A1; cytochrome P450 family 19 subfamily A member 1
Aliases: ARO, ARO1, CPV1, CYAR, CYP19, CYPXIX, P-450AROM
Location:15q21.2
Summary:This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and catalyzes the last steps of estrogen biosynthesis. Mutations in this gene can result in either increased or decreased aromatase activity; the associated phenotypes suggest that estrogen functions both as a sex steroid hormone and in growth or differentiation. Alternative promoter use and alternative splicing results in multiple transcript variants that have different tissue specificities. [provided by RefSeq, Dec 2016]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:aromatase
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
Show (46)

Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 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.

  • Testicular Cancer
  • Sequence Alignment
  • Antineoplastic Agents, Hormonal
  • Drug Resistance
  • Uterine Cancer
  • Promoter Regions
  • Estrogen Receptors
  • Genotype
  • Young Adult
  • Smoking
  • Tumor Stem Cell Assay
  • Hormone-Dependent Cancers
  • Aromatase Inhibitors
  • Estrogen Receptor alpha
  • Steroid Isomerases
  • Ovarian Cancer
  • Transcriptional Activation
  • Risk Factors
  • Cell Proliferation
  • Polymorphism
  • Receptors, Progesterone
  • Aromatase
  • Nucleic Acid Regulatory Sequences
  • Chromosome 15
  • Transcription
  • Unified Medical Language System
  • Signal Transduction
  • Sweden
  • Nitriles
  • Uncoupling Protein 2
  • Weight Gain
  • Estrogens
  • Steroidogenic Factor 1
  • Breast Cancer
  • Stomach Cancer
  • Transcription Factors
  • Vitamin D
  • Case-Control Studies
  • Cancer Gene Expression Regulation
  • Translocation
  • Cervical Cancer
  • Repetitive Sequences, Nucleic Acid
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: CYP19A1 (cancer-related)

Licznerska B, Szaefer H, Wierzchowski M, et al.
Resveratrol and its methoxy derivatives modulate the expression of estrogen metabolism enzymes in breast epithelial cells by AhR down-regulation.
Mol Cell Biochem. 2017; 425(1-2):169-179 [PubMed] Related Publications
Our earlier studies have shown that compared to resveratrol, its analogs with ortho-methoxy substituents exert stronger antiproliferative and proapoptotic activity. Since estrogens are considered the major risk factors of breast carcinogenesis, the aim of this study was to evaluate the effect of 3,4,2'-trimethoxy (3MS), 3,4,2',4'-tetramethoxy (4MS), and 3,4,2',4',6'-pentamethoxy (5MS) trans-stilbenes on the constitutive expression of the enzymes involved in estrogen metabolism, as well as receptors: AhR and HER2 in breast epithelial cell line MCF10A. The results showed different effect of resveratrol and its methoxy derivatives on the expression of genes encoding key enzymes of estrogen synthesis and catabolism. Resveratrol at the doses of 1 and 5 µmol/L increased the level of CYP19 transcript and protein level, while 5MS reduced mRNA transcript of both CYP19 and STS genes. Resveratrol and all its derivatives reduced also SULT1E1 mRNA transcript level. The reduced expression of AhR, CYP1A1, and 1B1 was also found as a result of treatment with these compounds. The most significant changes were found in the case of AhR. The most potent inhibitor of CYP1A1 and 1B1 genes expression was 5MS, which reduced the levels of mRNA transcript and protein of both CYPs from 31 to 89% of the initial levels. These results indicate that methoxy derivatives of resveratrol might be efficient modulators of estrogen metabolism. Moreover, the number of methoxy groups introduced to stilbene structure may play a certain role in this effect.

Borrie AE, Kim RB
Molecular basis of aromatase inhibitor associated arthralgia: known and potential candidate genes and associated biomarkers.
Expert Opin Drug Metab Toxicol. 2017; 13(2):149-156 [PubMed] Related Publications
INTRODUCTION: Aromatase inhibitors (AIs) are routinely used for the adjuvant treatment of women with hormone receptor-positive early breast cancer. AIs are widely prescribed in the postmenopausal setting, as they are effective at preventing recurrence. However, their use is complicated by significant adverse effects, particularly arthralgia, noted in up to 50% of treated patients, and thereby affects quality of life and AI compliance. The mechanism by which AIs cause arthralgia is largely unknown, although there is a growing body of literature which suggests that there may be multiple intersecting mechanisms. Areas covered: This review describes the evidence for the mechanistic basis of AI arthralgia as well as potential pathways that could contribute to the development of AI associated arthralgia. Expert opinion: Interplay of multiple factors, such as interpatient variability in AI metabolism, possibly related to pharmacogenetic factors, the sudden decline of estrogen synthesis, vitamin D status, as well as upregulation of cytokines and inflammation pathways may precipitate or exacerbate muscle and joint pain are linked during AI therapy. However, much more research is needed in this area given the frequency and severity of AI-associated arthralgia.

Tüzüner MB, Öztürk T, Eronat AP, et al.
Evaluation of Local CYP17A1 and CYP19A1 Expression Levels as Prognostic Factors in Postmenopausal Invasive Ductal Breast Cancer Cases.
Biochem Genet. 2016; 54(6):784-802 [PubMed] Related Publications
There is growing attention focused on local estrogen production in the breast tissue and its possible role in breast cancer initiation and progression. Understanding the underlying mechanisms for estrogen synthesis and the microenvironment consisting of tumor and its surrounding adipose tissue might open new avenues in breast cancer prevention, prognosis and treatment. In order to obtain insight, we compared peritumoral and tumor tissue expressions of CYP17A1 and CYP19A1 genes, which play an important role in estrogen biosynthesis. The paired tissue samples of 20 postmenopausal ER(+)/PR(+) patients diagnosed with invasive ductal breast cancer were studied. In addition, 12 breast tissue samples obtained from premenopausal women without a history of breast cancer were also investigated as representative of normal conditions. Peritumoral adipose tissues expressed CYP19A1 approximately threefold higher than tumor itself (p = 0.001). A nonsignificant trend toward low expression of CYP17A1 was observed in peritumoral compared to tumor tissue (p = 0.687). Clinicopathological parameters and patient characteristics which are accepted as risk factors for breast cancer were also associated with individual and combined expressions of CYP17A1 and CYP19A1. This study offers that evaluation of CYP17A1 and CYP19A1 local expression levels might be useful for deciding on personalized treatment approaches and more accurate diagnosis, when evaluated together with several clinicopathological and disease risk factors. Considering the key role of these CYPs in estrogen synthesis, determining their expression levels may be useful as a postdiagnostic marker and for choosing the right treatment method in addition to the conventional approach.

Liu X, Low SK, Boddy AV
The implications of genetic variation for the pharmacokinetics and pharmacodynamics of aromatase inhibitors.
Expert Opin Drug Metab Toxicol. 2016; 12(8):851-63 [PubMed] Related Publications
INTRODUCTION: Breast cancer is the most common female cancer and remains a serious public health concern worldwide. Third-generation aromatase inhibitors (AIs) are widely used in postmenopausal women with estrogen receptor positive breast cancer. However, there is marked interindividual variability in terms of the efficacy and incidence of adverse events following treatment with AIs. Pharmacogenetics has the potential to predict clinical outcomes based on patients' genetic information, paving the way towards personalized treatment.
AREAS COVERED: This article reviews pharmacogenetic studies of AIs, including pharmacokinetic and pharmacodynamic aspects, highlighting those studies where the efficacy and adverse events of AIs have been examined using both candidate gene and genome-wide approaches.
EXPERT OPINION: Pharmacogenetics is a promising approach to develop personalized medicine with AIs. However, the application of pharmacogenetics to predict therapeutic efficacy and adverse events in breast cancer patients is still far from implementation in routine clinical practice. Large, comprehensive, multicenter studies that simultaneously evaluate multiple genes and pathways, including rare variants, are warranted in order to produce reliable and informative results. The ultimate aim is to develop clinically-relevant guidelines for breast cancer therapy.

Farzaneh F, Noghabaei G, Barouti E, et al.
Analysis of CYP17, CYP19 and CYP1A1 Gene Polymorphisms in Iranian Women with Breast Cancer.
Asian Pac J Cancer Prev. 2016; 17 Spec No.:23-6 [PubMed] Related Publications
Breast cancer (BC) is the most common cancer and the second cause of mortality in women all around the world. It is caused by several factors including genetic determinants, so that both genetic susceptibility factors and environmental factors are involved in the etiology. Significance of genes functioning in steroid hormone synthesis and metabolism are well established in breast cancer susceptibility. In this study, 134 women with BC and 135 normal controls were analyzed for their genotypes for the polymorphisms, rs743572, rs10046 and rs4646903, resided in CYP17, CYP19 and CYP1A1 genes, respectively. Significant differences in distributions of allele and genotype frequencies were found for the rs10046 polymorphism in CYP19 (p-value=0.01, OR (CI 95%) =1.59 (1.1-2.3), p-value=0.04, OR (CI 95%) =1.7 (1.1-2.5) respectively). For rs743,572 and rs 4646903 polymorphisms, no significant associations were observed. A significant association was observed between the rs10046 polymorphism of the CYP19gene and breast cancer in Iranian patients. Due to inconsistent previous results, more studies in different populations with larger sample sizes are indicated.

Spillane AJ
What is new in the surgical management and prevention of breast cancer?
Med J Aust. 2016; 204(8):311-4 [PubMed] Related Publications
Breast cancer is the most common malignancy in Australian women. As most women now survive breast cancer, improving quality-of-life outcomes is increasingly important and major changes are occurring in breast surgery to meet this challenge. Use of neoadjuvant chemotherapy results in lower mastectomy rates, broader surgical options and less surgical morbidity. Oncoplastic breast surgery (OBS) facilitates less frequent need for mastectomy, better aesthetic outcomes and improved quality of life. Immediate breast reconstruction (IBR) improves quality of life and can be considered in a large proportion of women requiring mastectomy; however, Australia's rate of IBR is low compared with similar countries. Breast cancer risk reduction can be achieved with lifestyle modifications and, in women at high risk, chemoprevention with selective oestrogen receptor modulators or aromatase inhibitors. Bilateral prophylactic mastectomy is an option for BRCA gene mutation carriers or those women otherwise established to have a high level of risk. Contralateral prophylactic mastectomy (CPM) is increasingly performed at the time of initial breast cancer management, largely driven by patient preference. However, CPM does not improve survival and has similar rates of complications as therapeutic mastectomy. It should be cautiously considered, with full discussion of risks and benefits. Breast Surgeons of Australia and New Zealand (BreastSurgANZ) coordinates training of most new breast surgeons and is fostering a broader range of multidisciplinary oncology, OBS and IBR skills in its members. The BreastSurgANZ Quality Audit monitors the quality of care provided by members. Training breast surgeons now have access to a Graduate Certificate in Surgery (Breast Surgery) to broaden their knowledge base.

Kopp TI, Jensen DM, Ravn-Haren G, et al.
Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial.
BMC Cancer. 2016; 16:283 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and interaction with aromatase (encoded by CYP19A1). Use of non-steroidal anti-inflammatory drugs (NSAID) may also affect circulating sex-hormone levels by modifying PPARγ activity.
METHODS: In the present study we assessed whether genetic variation in CYP19A1 is associated with risk of BC in a case-control study group nested within the Danish "Diet, Cancer and Health" cohort (ncases = 687 and ncontrols = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions. Association between the CYP19A1 polymorphisms and hormone levels was also examined among 339 non-HRT users. Incidence rate ratios were calculated based on Cox' proportional hazards model. Furthermore, we performed a pilot randomised controlled trial to determine the effect of the PPARG Pro(12)Ala polymorphism and the PPARγ stimulator Ibuprofen on sex-hormone levels following alcohol intake in postmenopausal women (n = 25) using linear regression.
RESULTS: Genetic variations in CYP19A1 were associated with hormone levels (estrone: P rs11070844 = 0.009, estrone sulphate: P rs11070844 = 0.01, P rs749292 = 0.004, P rs1062033 = 0.007 and P rs10519297 = 0.03, and sex hormone-binding globulin (SHBG): P rs3751591 = 0.03) and interacted with alcohol intake in relation to hormone levels (estrone sulphate: P interaction/rs2008691 = 0.02 and P interaction/rs1062033= 0.03, and SHBG: P interaction/rs11070844 = 0.03). CYP19A1/rs3751591 was both associated with SHBG levels (P = 0.03) and with risk of BC (Incidence Rate Ratio = 2.12; 95 % Confidence Interval: 1.02-4.43) such that homozygous variant allele carriers had increased levels of serum SHBG and were at increased risk of BC. Acute intake of alcohol decreased blood estrone (P = <0.0001), estrone sulphate (P = <0.0001), and SHBG (P = 0.009) levels, whereas Ibuprofen intake and PPARG Pro(12)Ala genotype had no effect on hormone levels.
CONCLUSIONS: Our results suggest that genetically determined variation in CYP19A1 is associated with differences in sex hormone levels. However, the genetically determined differences in sex hormone levels were not convincingly associated with BC risk. The results therefore indicate that the genetically determined variation in CYP19A1 contributes little to BC risk and to alcohol-mediated BC risk.
TRIAL REGISTRATION: NCT02463383, June 3, 2015.

Brureau L, Moningo D, Emeville E, et al.
Polymorphisms of Estrogen Metabolism-Related Genes and Prostate Cancer Risk in Two Populations of African Ancestry.
PLoS One. 2016; 11(4):e0153609 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Estrogens are thought to play a critical role in prostate carcinogenesis. It has been suggested that polymorphisms of genes encoding enzymes involved in estrogen metabolism are risk factors for prostate cancer. However, few studies have been performed on populations of African ancestry, which are known to have a high risk of prostate cancer.
OBJECTIVE: We investigated whether functional polymorphisms of CYP17, CYP19, CYP1B1, COMT and UGT1A1 affected the risk of prostate cancer in two different populations of African ancestry.
METHODS: In Guadeloupe (French West Indies), we compared 498 prostate cancer patients and 565 control subjects. In Kinshasa (Democratic Republic of Congo), 162 prostate cancer patients were compared with 144 controls. Gene polymorphisms were determined by the SNaPshot technique or short tandem repeat PCR analysis. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI).
RESULTS: The AA genotype and the A allele of rs4680 (COMT) appeared to be inversely associated with the risk of prostate cancer in adjusted models for both Afro-Caribbean and native African men. For the A allele, a significant inverse association was observed among cases with low-grade Gleason scores and localized clinical stage, in both populations.
CONCLUSIONS: These preliminary results support the hypothesis that polymorphisms of genes encoding enzymes involved in estrogen metabolism may modulate the risk of prostate cancer in populations of African ancestry.

Scharl A, Salterberg A, Untch M, et al.
Treatment Modification in Young Breast Cancer Patients.
Oncol Res Treat. 2016; 39(3):122-8 [PubMed] Related Publications
Patients not older than 40 years are referred to as young patients. These women benefit from chemo-, endocrine and anti-HER2 therapy to a similar degree as older women. Surgery and radiation therapy also follow the same recommendations. This manuscript deals with the following topics that need special consideration in young women: endocrine therapy and ovarian suppression; fertility protection and family planning; and genetic counselling. There is an on-going debate on whether tamoxifen is sufficient as an endocrine treatment in young patients with endocrine-responsive tumours or whether suppression of ovarian function in combination with tamoxifen or aromatase inhibitor should be preferred. Recent data suggest a benefit from ovarian suppression plus exemestane in women of 35 years or younger with high-risk breast cancer. However, increased side effects bear the risk of lesser compliance, which eventually results in higher mortality. Child bearing is nowadays frequently postponed to the 4th decade of life, thereby increasing the number of women who have not yet finished their reproductive desires when diagnosed with breast cancer. These patients are in urgent need of counselling for fertility protection. Breast cancer diagnosis at young age is an indication for a possible mutation in breast cancer susceptibility genes. This has an impact on the cancer risk of the whole family, especially the offspring. Drugs that are specifically targeted to cancer cells with genetic alterations that impair DNA repair are already entering the arsenal of oncologists.

Simonsson M, Veerla S, Markkula A, et al.
CYP1A2--a novel genetic marker for early aromatase inhibitor response in the treatment of breast cancer patients.
BMC Cancer. 2016; 16:256 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Endocrine resistance is a major obstacle to optimal treatment effect in breast cancer. Some genetic markers have been proposed to predict response to aromatase inhibitors (AIs) but the data is insufficient. The aim of the study was to find new genetic treatment predictive markers of AIs.
METHODS: The ongoing population-based BC-blood study in Lund, Sweden includes women with primary breast cancer. This paper is based on AI-treated patients with estrogen receptor positive tumors who underwent breast cancer surgery in 2002-2008. First, an exploratory analysis of 1931 SNPs in 227 genes involved in absorption, distribution, metabolism, and elimination of multiple medications, using DMET™ chips, was conducted in a subset of the cohort with last follow-up in December 31st 2011 (13 cases, 11 controls). Second, selected SNPs from the first analysis were re-analyzed concerning risk for early breast cancer events in the extended cohort of 201 AI-treated with last follow-up in June 30th 2014. Clinical data were obtained from medical records and population registries.
RESULTS: Only CYP1A2 rs762551 C-allele was significantly associated with increased risk for early events in the 24 patients (P = 0.0007) and in the extended cohort, adjusted Hazard ratio (HR) 2.22 (95% CI 1.03-4.80). However, the main prognostic impact was found within five years, adjusted HR 7.88 (95% CI 2.13-29.19). The impact of the CYP1A2 rs762551 C-allele was modified by a functional polymorphism in the regulator gene AhR Arg554Lys (G > A). Compared to patients who were homozygous for the major allele in both genes (CYP1A2 A/A and AhR G/G), a 9-fold risk for early events was found in patients who had at least one minor allele in both genes, adjusted HR 8.95 (95% CI 2.55-31.35), whereas patients with at least one minor allele in either but not both genes had a 3-fold risk for early events, adjusted HR 2.81 (95% CI 1.07-7.33). The impact of CYP1A2 rs762551 C-allele was also modified by the CYP19A1 rs4646 C/C, adjusted HR 3.39 (95% CI 1.60-7.16) for this combination. This association was strongest within the first five years, adjusted HR 10.42 (95% CI 3.45-31.51).
CONCLUSION: CYP1A2 rs762551 was identified as a new potential predictive marker for early breast cancer events in AI-treated breast cancer patients. Moreover, combined genotypes of CYP1A2 rs762551 and CYP19A1 rs4646 or AhR Arg554Lys could further improve prediction of early AI-treatment response. If confirmed, these results may provide a way to more personalized medicine.

Liu J, Prager-van der Smissen WJ, Look MP, et al.
GATA3 mRNA expression, but not mutation, associates with longer progression-free survival in ER-positive breast cancer patients treated with first-line tamoxifen for recurrent disease.
Cancer Lett. 2016; 376(1):104-9 [PubMed] Related Publications
In breast cancer, GATA3 mutations have been associated with a favorable prognosis and the response to neoadjuvant aromatase inhibitor treatment. Therefore, we investigated whether GATA3 mutations predict the outcome of tamoxifen treatment in the advanced setting. In a retrospective study consisting of 235 hormone-naive patients with ER-positive breast cancer who received tamoxifen as first-line treatment for recurrent disease, GATA3 mutations (in 14.0% of patients) did not significantly associate with either the overall response rate (ORR) or with the length of progression-free survival (PFS) after the start of tamoxifen therapy. Interestingly, among 148 patients for whom both mutation and mRNA expression data were available, GATA3 mutations associated with an increased expression of GATA3. However, only 23.7% of GATA3 high tumors had a mutation. Evaluation of the clinical significance of GATA3 mRNA revealed that it was associated with prolonged PFS, but not with the ORR, also in multivariate analysis. Thus, GATA3 mRNA expression, but not GATA3 mutation, is an independent predictor of prolonged PFS in ER-positive breast cancer patients who received first-line tamoxifen for recurrent disease. Besides GATA3 mutation, other mechanisms must exist that underlie increased GATA3 levels.

Fentiman IS
Male breast cancer is not congruent with the female disease.
Crit Rev Oncol Hematol. 2016; 101:119-24 [PubMed] Related Publications
It has become customary to extrapolate from the results of treatment trials for female breastcancer and apply them to males with the disease. In the absence of results from national and international randomised trials for male breast cancer (MBC) this appears superficially to be an appropriate response. Closer examination of available data reveals that aspects of the aetiology and treatment of MBC do not fit the simplistic model that men usually have endocrine sensitive tumours which behave like those in postmenopausal women. Most females and males with breast cancer have none of the recognised risk factors, indicating the gaps in our knowledge of the epidemiology of this disease. Several studies have compared epidemiological risk factors for MBC and female breast cancer (FBC) but many have been blighted by small numbers. In comparison with FBC there is a larger proportion of BRCA2 tumours, (occurring in 10% of MBC), and underrepresentation of BRCA1 tumours (found in only 1%), suggesting significant differences in the genetic aetiology of MBC and FBC. Genome-wide association studies in FBC reported single nucleotide polymorphisms (SNPs) in 12 novel independent loci were consistently associated with disease but for MBC 2 SNPs had a significantly increased risk. Molecular profiles of matched cancers in males and females showed a gender-associated modulation of major processes including energy metabolism, regulation of translation, matrix remodelling and immune recruitment. Immunohistochemistry for kinase inhibitor proteins (KIPs) p27Kip1 and p21Waf1 indicate a significant difference in the immunostaining of tumours from male patients compared with females. MBC is almost always estrogen receptor positive (ER+ve) and so systemic treatment is usually endocrine. With evidence in FBC that aromatase inhibitors are more effective than tamoxifen in the postmenopausal it was seemingly logical that the same would be true for MBC. Results however suggest less efficacy with AIs and an increase in risk of mortality compared to tamoxifen. The overall survival in male breast cancer was significantly better after adjuvant treatment with tamoxifen compared to an aromatase inhibitor. These important biological differences point the way to the development of new therapies for MBC based on differences rather than similarities with FBC.

Ueno T, Saji S, Sugimoto M, et al.
Clinical significance of the expression of autophagy-associated marker, beclin 1, in breast cancer patients who received neoadjuvant endocrine therapy.
BMC Cancer. 2016; 16:230 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Neoadjuvant endocrine therapy (NAE) has been employed to improve surgical outcomes for hormone receptor-positive breast cancers in postmenopausal women. Endocrine responsiveness is estimated by expressions of hormone receptors, but its heterogeneity has been recognized. Autophagy is an evolutionally conserved process associated with cell survival and cell death and has been implicated in cancer treatment.
METHODS: In order to examine the possible association between autophagy and response to endocrine therapy, we evaluated the status of autophagy-associated markers, beclin 1 and LC3, and apoptosis-associated markers, TUNEL and M30, in pre- and post-treatment specimens from 71 patients in a multicenter prospective study of neoadjuvant exemestane (JFMC34-0601).
RESULTS: Immunoreactivity of the autophagy-associated markers, beclin 1 and LC3, in carcinoma cells increased in 14% and 52% of the patients, respectively, following the exemestane treatment. These increases were statistically significant (beclin 1, p = 0.016, N = 49; LC3, p < 0.0001, N = 33). The status of M30 immunoreactivity decreased (p = 0.008, N = 47) and TUNEL remained unchanged (N = 53). In addition, tumors with pre-treatment stromal beclin 1 immunoreactivity revealed poor clinical and pathological responses compared with those without stromal beclin 1 immunoreactivity (25% vs 67% for clinical response, p = 0.011, N = 51; 0% vs 41% for pathological response, p = 0.0081, N = 49). Tumors with positive pre-treatment stromal beclin 1 had a higher baseline Ki-67 labeling index (both hot spot and overall average) than those without (p = 0.042 and 0.0075, respectively, N = 53). Results of logistic regression analyses revealed that stromal beclin 1 was a predictor for clinical and pathological responses while ER, PR, Ki-67, and stromal LC3 expressions were not.
CONCLUSIONS: Results of our present study demonstrated that beclin 1 and LC3 immunoreactivity increased in carcinoma cells following exemestane treatment and that the status of pre-treatment stromal beclin 1 is associated with higher carcinoma cell proliferation and poor clinical and pathological responses to NAE.
TRIAL REGISTRATION: UMIN C000000345 (2006/03/06).

Hu K, Tian Y, Du Y, et al.
Atrazine promotes RM1 prostate cancer cell proliferation by activating STAT3 signaling.
Int J Oncol. 2016; 48(5):2166-74 [PubMed] Related Publications
Atrazine, a widely used pesticide, is frequently detected in soil and surface water, which alarms epidemiologists and medical professionals because of its potential deleterious effects on health. Indeed, atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. Both animal and human studies have suggested that atrazine is possibly carcinogenic, although discrepant results have been reported. In this study, RM1 cells were used to explore the atrazine effects on prostate cancer. Proliferation, migration and invasion of RM1 cells were assessed by colony formation, wound-healing and invasion assays, respectively, after in vitro exposure to atrazine. In addition, an RM1 cell xenograft model was generated to evaluate the effects of atrazine in vivo. To explore the molecular mechanisms, qRT‑PCR, immunohistochemistry, and western blot analyses were employed to detect mRNA and protein levels of STAT3 signaling and cell cycle related proteins, including p53, p21, cyclin B1 and cyclin D1. Interestingly, RM1 cell proliferation was increased after treatment with atrazine, concomitantly with STAT3 signaling activation. These results suggest that atrazine promotes RM1 cell growth in vitro and in vivo by activating STAT3 signaling.

Takagi M, Miki Y, Miyashita M, et al.
Intratumoral estrogen production and actions in luminal A type invasive lobular and ductal carcinomas.
Breast Cancer Res Treat. 2016; 156(1):45-55 [PubMed] Related Publications
The great majority of invasive lobular carcinoma (ILC) is estrogen-dependent luminal A type carcinoma but the details of estrogen actions and its intratumoral metabolism have not been well studied compared to invasive ductal carcinoma (IDC). We first immunolocalized estrogen-related enzymes including estrogen sulfotransferase (EST), estrogen sulfatase (STS), 17β-hydroxysteroid dehydrogenase (HSD) 1/2, and aromatase. We then evaluated the tissue concentrations of estrogens in ILC and IDC and subsequently estrogen-responsive gene profiles in these tumors in order to explore the possible differences and/or similarity of intratumoral estrogen environment of these two breast cancer subtypes. The status of STS and 17βHSD1 was significantly lower in ILCs than IDCs (p = 0.022 and p < 0.0001), but that of EST and 17βHSD2 vice versa (p < 0.0001 and p = 0.0106). In ILCs, tissue concentrations of estrone and estradiol were lower than those in IDCs (p = 0.0709 and 0.069). In addition, the great majority of estrogen response genes tended to be lower in ILCs. Among those genes above, FOXP1 was significantly higher in ILCs than in IDCs (p = 0.002). FOXP1 expression was reported to be significantly higher in relapse-free IDC patients treated with tamoxifen. Therefore, tamoxifen may be considered an option of endocrine therapy for luminal A type ILC patients. This is the first study to demonstrate the detailed and comprehensive status of intratumoral production and metabolism of estrogens and the status of estrogen response genes in luminal A-like ILC with comparison to those in luminal A-like IDCs.

Koukoura O, Sifakis S, Spandidos DA
DNA methylation in endometriosis (Review).
Mol Med Rep. 2016; 13(4):2939-48 [PubMed] Free Access to Full Article Related Publications
Endometriosis is defined by the presence and growth of functional endometrial tissue, outside the uterine cavity, primarily in the ovaries, pelvic peritoneum and rectovaginal septum. Although it is a benign disease, it presents with malignant characteristics, such as invasion to surrounding tissues, metastasis to distant locations and recurrence following treatment. Accumulating evidence suggests that various epigenetic aberrations may play an essential role in the pathogenesis of endometriosis. Aberrant DNA methylation represents a possible mechanism repsonsible for this disease, linking gene expression alterations observed in endometriosis with hormonal and environmental factors. Several lines of evidence indicate that endometriosis may partially be due to selective epigenetic deregulations influenced by extrinsic factors. Previous studies have shed light into the epigenetic component of endometriosis, reporting variations in the epigenetic patterns of genes known to be involved in the aberrant hormonal, immunologic and inflammatory status of endometriosis. Although recent studies, utilizing advanced molecular techniques, have allowed us to further elucidate the possible association of DNA methylation with altered gene expression, whether these molecular changes represent the cause or merely the consequence of the disease is a question which remains to be answered. This review provides an overview of the current literature on the role of DNA methylation in the pathophysiology and malignant evolution of endometriosis. We also provide insight into the mechanisms through which DNA methylation-modifying agents may be the next step in the research of the pharmaceutical treatment of endometriosis.

Abu N, Akhtar MN, Yeap SK, et al.
Flavokawain B induced cytotoxicity in two breast cancer cell lines, MCF-7 and MDA-MB231 and inhibited the metastatic potential of MDA-MB231 via the regulation of several tyrosine kinases In vitro.
BMC Complement Altern Med. 2016; 16:86 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The kava-kava plant (Piper methysticum) is traditionally consumed by the pacific islanders and has been linked to be involved in several biological activities. Flavokawain B is a unique chalcone, which can be found in the roots of the kava-kava plant. In this study, the operational mechanism of the anti-cancer activity of a synthetic Flavokawain B (FKB) on two breast cancer cell lines, MCF-7 and MDA-MB231 was investigated.
METHOD: Several in vitro assays were attempted such as MTT, flow cytometry of cell cycle analysis, annexin V analysis, and JC-1 analysis to detect apoptosis. Moreover, in vitro metastasis assays were also performed such as transwell migration assay, invasion assay, rat aorta ring and HUVEC tube formation. Molecular analysis of related genes and proteins were conducted using real-time PCR and proteome profiler analysis.
RESULTS: Based on our results, apoptosis was induced when both MCF-7 and MDA-MB231 were treated with FKB. A significant G2/M arrest was seen in MDA-MB231 cells. Additionally, FKB also inhibited the in vitro migration and invasion in MDA-MB231 cells in a dose dependent manner. Moreover, FKB can be a potential inhibitor in angiogenesis as it suppressed the formation of vessels in HUVEC cells as well as in the ex-vivo rat aortic ring assay.
CONCLUSION: Our findings suggested that FKB also regulated several receptor tyrosine kinases. Overall, FKB is not only a potential candidate to be an anti-cancer agent, but as an anti-metastatic agent as well.

Reijm EA, Sieuwerts AM, Smid M, et al.
An 8-gene mRNA expression profile in circulating tumor cells predicts response to aromatase inhibitors in metastatic breast cancer patients.
BMC Cancer. 2016; 16:123 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Molecular characterization of circulating tumor cells (CTC) is promising for personalized medicine. We aimed to identify a CTC gene expression profile predicting outcome to first-line aromatase inhibitors in metastatic breast cancer (MBC) patients.
METHODS: CTCs were isolated from 78 MBC patients before treatment start. mRNA expression levels of 96 genes were measured by quantitative reverse transcriptase polymerase chain reaction. After applying predefined exclusion criteria based on lack of sufficient RNA quality and/or quantity, the data from 45 patients were used to construct a gene expression profile to predict poor responding patients, defined as disease progression or death <9 months, by a leave-one-out cross validation.
RESULTS: Of the 45 patients, 19 were clinically classified as poor responders. To identify them, the 75% most variable genes were used to select genes differentially expressed between good and poor responders. An 8-gene CTC predictor was significantly associated with outcome (Hazard Ratio [HR] 4.40, 95% Confidence Interval [CI]: 2.17-8.92, P < 0.001). This predictor identified poor responding patients with a sensitivity of 63% and a positive predictive value of 75%, while good responding patients were correctly predicted in 85% of the cases. In multivariate Cox regression analysis, including CTC count at baseline, the 8-gene CTC predictor was the only factor independently associated with outcome (HR 4.59 [95% CI: 2.11-9.56], P < 0.001). This 8-gene signature was not associated with outcome in a group of 71 MBC patients treated with systemic treatments other than AI.
CONCLUSIONS: An 8-gene CTC predictor was identified which discriminates good and poor outcome to first-line aromatase inhibitors in MBC patients. Although results need to be validated, this study underscores the potential of molecular characterization of CTCs.

Sakai M, Martinez-Arguelles DB, Aprikian AG, et al.
De novo steroid biosynthesis in human prostate cell lines and biopsies.
Prostate. 2016; 76(6):575-87 [PubMed] Related Publications
BACKGROUND: Intratumoral androgen formation may be a factor in the development of prostate cancer (PCa), particularly castration-resistant prostate cancer (CRPC). To evaluate the ability of the human prostate to synthesize de novo steroids, we examined the expression of key enzymes and proteins involved in steroid biosynthesis and metabolism.
METHODS: Using TissueScan™ Cancer qPCR Arrays and quantitative RT-PCR, we performed comparative gene expression analyses between various prostate cell lines and biopsies, including normal, hyperplastic, cancerous, and androgen-deprived prostate cells lines, as well as normal, benign prostate hyperplasia (BPH), PCa, and CRPC human specimens. These studies were complemented with steroid biosynthesis studies in normal and BPH cells.
RESULTS: Normal human prostate WPMY-1 and WPE1-NA22, benign prostate hyperplasia BPH-1, and cancer PC-3, LNCaP, and VCaP cell lines, as well as normal, BPH, PCa, and CRPC specimens, were used. Although all cell lines express mRNA encoding for hydroxymethylglutaryl-CoA reductase (HMGCR), the mitochondrial translocator protein TSPO and cholesterol side chain cleavage enzyme CYP11A1 were only observed in WPMY-1, BPH-1, and LNCaP cells. HSD3B1, HSD3B2, and CYP17A1 are involved in androgen formation and were not found in most cell lines. WPE1-NA22 and BPH-1 cells were unable to synthesize de novo steroids from mevalonate. Moreover, androgen-deprived cells did not have alterations in the expression of enzymes that could lead to de novo steroid formation. All prostate specimens expressed TSPO and CYP11A1. HSD3B1/2, CYP17A1, HSD17B5, and CYP19A1 mRNA expression was distinct to the profile observed in cells lines. The majority of BPH (90.9%) and PCa (83.1%) specimens contained CYP17A1, compared to control (normal) specimens (46.7%). BPH (82%), PCa (59%), normal (40%), and CRPC (34%) specimens expressed the four key enzymes that metabolize cholesterol to androgens.
CONCLUSION: These studies question the use of prostate cell lines to study steroid biosynthesis and demonstrate that human prostate samples contain transcripts encoding for key steroidogenic enzymes and proteins indicating that they have the potential to synthesize de novo steroids. We propose CYP17A1 as a candidate enzyme that can be used for patient stratification and treatment in BPH and PCa.

Saita C, Goto R, Aruga T, et al.
Invasive papillary carcinoma treated with neoadjuvant endocrine therapy in which pathological complete response was achieved.
BMC Res Notes. 2016; 9:46 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Invasive papillary carcinoma is a rare type of invasive ductal carcinoma. Neoadjuvant endocrine therapy is now considered as an optional therapy for postmenopausal women with hormone receptor-positive breast cancers, including invasive papillary carcinoma.
CASE PRESENTATION: We discuss the case of an 83-year-old postmenopausal Japanese female with hormone receptor-positive invasive papillary carcinoma who started treatment with an aromatase inhibitor and achieved pathological complete response after 12 months of endocrine treatment.
CONCLUSION: Appropriate drugs and durations of neoadjuvant endocrine treatment have yet to be established. Continuing therapy with an aromatase inhibitor until the best clinical response is achieved may represent one of the best strategies in neoadjuvant endocrine therapy.

Lintermans A, Van Asten K, Jongen L, et al.
Genetic variant in the osteoprotegerin gene is associated with aromatase inhibitor-related musculoskeletal toxicity in breast cancer patients.
Eur J Cancer. 2016; 56:31-6 [PubMed] Related Publications
BACKGROUND: Aromatase inhibitor (AI) therapy is associated with musculoskeletal (MS) toxicity, which adversely affects quality of life and therapy adherence. Our objective was to evaluate whether genetic variants may predict endocrine therapy-related MS pain and hot flashes in a prospective observational cohort study.
PATIENTS & METHODS: 254 early breast cancer patients starting AI (n = 159) or tamoxifen therapy (n = 95) were included in this genetic biomarker study. MS and vasomotor symptoms were assessed at baseline and after 3, 6 and 12 months of therapy. AI-induced MS pain was defined as an increase in arthralgia or myalgia relative to baseline. Single nucleotide polymorphisms (SNP) in candidate genes involved in oestrogen signalling or previously associated with AI-related MS pain or oestrogen levels were selected.
RESULTS: Overall, 13 SNPs in CYP19, CYP17, osteoprotegerin (OPG) and oestrogen receptor 1 exhibited an allele frequency >0.05 and were included in the analysis. Patients carrying the G allele of rs2073618 in OPG experienced significantly more AI-induced MS toxicity compared to the wildtype allele, after correction for multiple testing (P = 0.046). Furthermore, this SNP was associated with severity of pain (P = 0.018). No association was found with regard to the other SNPs, both in AI and tamoxifen-treated patients. Neither could an association with vasomotor symptoms be demonstrated.
CONCLUSION: The SNP rs2073618 in OPG is associated with an increased risk of MS symptoms and pain with AI therapy, which has not been reported previously. Validation of this finding in larger cohorts and further functional studies are required.

Park YJ, Ahn HY, Kim HR, et al.
Ginkgo biloba extract EGb 761-mediated inhibition of aromatase for the treatment of hormone-dependent breast cancer.
Food Chem Toxicol. 2016; 87:157-65 [PubMed] Related Publications
Ginkgo biloba has been used in herbal medicines for thousands of years. Although a standard G. biloba extract, EGb 761 has been used to improve cognition in breast cancer patients, its effects on breast cancer are unknown. Therefore, we investigated the antitumorigenic effects of EGb 761 using an in vitro cell model and an in vivo xenograft model. EGb 761 significantly inhibited aromatase activity in aromatase over-expressing MCF-7 cells (MCF-7 AROM). In addition, EGb 761 exposure reduced cytochrome p450 aromatase (CYP19) mRNA and protein expression; CYP19 promoter I.3 and PII expression particularly decreased. These inhibitory effects on aromatase were accompanied by reduced 17β-estradiol levels in MCF-7 AROM cells. For elucidating antitumorigenic effects, MCF-7 AROM cells were implanted in BALB/c nude mice prior to oral EGb 761 treatment for 3 weeks. EGb 761 reduced the tumor size and significantly reduced tumor CYP19 mRNA expression. Taken together, our results indicated that EGb 761 inhibited aromatase and exerted antitumor effects on breast cancer cells both in vitro and in vivo. These findings suggest that EGb761 may be a useful aromatase inhibitor for the treatment for estrogen-sensitive breast cancer.

Sherr CJ, Beach D, Shapiro GI
Targeting CDK4 and CDK6: From Discovery to Therapy.
Cancer Discov. 2016; 6(4):353-67 [PubMed] Free Access to Full Article Related Publications
UNLABELLED: Biochemical and genetic characterization of D-type cyclins, their cyclin D-dependent kinases (CDK4 and CDK6), and the polypeptide CDK4/6 inhibitor p16(INK4)over two decades ago revealed how mammalian cells regulate entry into the DNA synthetic (S) phase of the cell-division cycle in a retinoblastoma protein-dependent manner. These investigations provided proof-of-principle that CDK4/6 inhibitors, particularly when combined with coinhibition of allied mitogen-dependent signal transduction pathways, might prove valuable in cancer therapy. FDA approval of the CDK4/6 inhibitor palbociclib used with the aromatase inhibitor letrozole for breast cancer treatment highlights long-sought success. The newest findings herald clinical trials targeting other cancers.
SIGNIFICANCE: Rapidly emerging data with selective inhibitors of CDK4/6 have validated these cell-cycle kinases as anticancer drug targets, corroborating longstanding preclinical predictions. This review addresses the discovery of these CDKs and their regulators, as well as translation of CDK4/6 biology to positive clinical outcomes and development of rational combinatorial therapies.

Hagberg Thulin M, Nilsson ME, Thulin P, et al.
Osteoblasts promote castration-resistant prostate cancer by altering intratumoral steroidogenesis.
Mol Cell Endocrinol. 2016; 422:182-91 [PubMed] Related Publications
The skeleton is the preferred site for prostate cancer (PC) metastasis leading to incurable castration-resistant disease. The increased expression of genes encoding steroidogenic enzymes found in bone metastatic tissue from patients suggests that up-regulated steroidogenesis might contribute to tumor growth at the metastatic site. Because of the overall sclerotic phenotype, we hypothesize that osteoblasts regulate the intratumoral steroidogenesis of castration resistant prostate cancer (CRPC) in bone. We here show that osteoblasts alter the steroidogenic transcription program in CRPC cells, closely mimicking the gene expression pattern described in CRPC. Osteoblast-stimulated LNCaP-19 cells displayed an increased expression of genes encoding for steroidogenic enzymes (CYP11A1, HSD3B1, and AKR1C3), estrogen signaling-related genes (CYP19A1, and ESR2), and genes for DHT-inactivating enzymes (UGT2B7, UGT2B15, and UGT2B17). The observed osteoblast-induced effect was exclusive to osteogenic CRPC cells (LNCaP-19) in contrast to osteolytic PC-3 and androgen-dependent LNCaP cells. The altered steroid enzymatic pattern was specific for the intratibial tumors and verified by immunohistochemistry in tissue specimens from LNCaP-19 xenograft tumors. Additionally, the overall steroidogenic effect was reflected by corresponding levels of progesterone and testosterone in serum from castrated mice with intratibial xenografts. A bi-directional interplay was demonstrated since both proliferation and Esr2 expression of osteoblasts were induced by CRPC cells in steroid-depleted conditions. Together, our results demonstrate that osteoblasts are important mediators of the intratumoral steroidogenesis of CRPC and for castration-resistant growth in bone. Targeting osteoblasts may therefore be important in the development of new therapeutic approaches.

Thomsen KG, Lyng MB, Elias D, et al.
Gene expression alterations associated with outcome in aromatase inhibitor-treated ER+ early-stage breast cancer patients.
Breast Cancer Res Treat. 2015; 154(3):483-94 [PubMed] Related Publications
Aromatase inhibitors (AI), either alone or together with chemotherapy, have become the standard adjuvant treatment for postmenopausal, estrogen receptor-positive (ER+) breast cancer. Although AIs improve overall survival, resistance is still a major clinical problem, thus additional biomarkers predictive of outcome of ER+ breast cancer patients treated with AIs are needed. Global gene expression analysis was performed on ER+ primary breast cancers from patients treated with adjuvant AI monotherapy; half experienced recurrence (median follow-up 6.7 years). Gene expression alterations were validated by qRT-PCR, and functional studies evaluating the effect of siRNA-mediated gene knockdown on cell growth were performed. Twenty-six genes, including TFF3, DACH1, RGS5, and GHR, were shown to exhibit altered expression in tumors from patients with recurrence versus non-recurrent (fold change ≥1.5, p < 0.05), and the gene expression alterations were confirmed using qRT-PCR. Ten of these 26 genes could be linked in a network associated with cellular proliferation, growth, and development. TFF3, which encodes for trefoil factor 3 and is an estrogen-responsive oncogene shown to play a functional role in tamoxifen resistance and metastasis of ER+ breast cancer, was also shown to be upregulated in an AI-resistant cell line model, and reduction of TFF3 levels using TFF3-specific siRNAs decreased the growth of both the AI-resistant and -sensitive parental cell lines. Moreover, overexpression of TFF3 in parental AI-sensitive MCF-7/S0.5 cells resulted in reduced sensitivity to the AI exemestane, whereas TFF3 overexpression had no effect on growth in the absence of exemestane, indicating that TFF3 mediates growth and survival signals that abrogate the growth inhibitory effect of exemestane. We identified a panel of 26 genes exhibiting altered expression associated with disease recurrence in patients treated with adjuvant AI monotherapy, including TFF3, which was shown to exhibit a growth- and survival-promoting effect in the context of AI treatment.

Thompson DJ, O'Mara TA, Glubb DM, et al.
CYP19A1 fine-mapping and Mendelian randomization: estradiol is causal for endometrial cancer.
Endocr Relat Cancer. 2016; 23(2):77-91 [PubMed] Free Access to Full Article Related Publications
Candidate gene studies have reported CYP19A1 variants to be associated with endometrial cancer and with estradiol (E2) concentrations. We analyzed 2937 single nucleotide polymorphisms (SNPs) in 6608 endometrial cancer cases and 37 925 controls and report the first genome wide-significant association between endometrial cancer and a CYP19A1 SNP (rs727479 in intron 2, P=4.8×10(-11)). SNP rs727479 was also among those most strongly associated with circulating E2 concentrations in 2767 post-menopausal controls (P=7.4×10(-8)). The observed endometrial cancer odds ratio per rs727479 A-allele (1.15, CI=1.11-1.21) is compatible with that predicted by the observed effect on E2 concentrations (1.09, CI=1.03-1.21), consistent with the hypothesis that endometrial cancer risk is driven by E2. From 28 candidate-causal SNPs, 12 co-located with three putative gene-regulatory elements and their risk alleles associated with higher CYP19A1 expression in bioinformatical analyses. For both phenotypes, the associations with rs727479 were stronger among women with a higher BMI (Pinteraction=0.034 and 0.066 respectively), suggesting a biologically plausible gene-environment interaction.

Wang X, Simpson ER, Brown KA
p53: Protection against Tumor Growth beyond Effects on Cell Cycle and Apoptosis.
Cancer Res. 2015; 75(23):5001-7 [PubMed] Related Publications
The tumor suppressor p53 has established functions in cancer. Specifically, it has been shown to cause cell-cycle arrest and apoptosis in response to DNA damage. It is also one of the most commonly mutated or silenced genes in cancer and for this reason has been extensively studied. Recently, the role of p53 has been shown to go beyond its effects on cell cycle and apoptosis, with effects on metabolism emerging as a key contributor to cancer growth in situations where p53 is lost. Beyond this, the role of p53 in the tumor microenvironment is poorly understood. The publication by Wang and colleagues demonstrates for the first time that p53 is a key negative regulator of aromatase and, hence, estrogen production in the breast tumor microenvironment. It goes further by demonstrating that an important regulator of aromatase, the obesity-associated and tumor-derived factor prostaglandin E2, inhibits p53 in the breast adipose stroma. This review presents these findings in the context of established and emerging roles of p53 and discusses possible implications for the treatment of breast cancer.

Oesterreich S, Henry NL, Kidwell KM, et al.
Associations between genetic variants and the effect of letrozole and exemestane on bone mass and bone turnover.
Breast Cancer Res Treat. 2015; 154(2):263-73 [PubMed] Free Access to Full Article Related Publications
Adjuvant therapy for hormone receptor (HR) positive postmenopausal breast cancer patients includes aromatase inhibitors (AI). While both the non-steroidal AI letrozole and the steroidal AI exemestane decrease serum estrogen concentrations, there is evidence that exemestane may be less detrimental to bone. We hypothesized that single nucleotide polymorphisms (SNP) predict effects of AIs on bone turnover. Early stage HR-positive breast cancer patients were enrolled in a randomized trial of exemestane versus letrozole. Effects of AI on bone mineral density (BMD) and bone turnover markers (BTM), and associations between SNPs in 24 candidate genes and changes in BMD or BTM were determined. Of the 503 enrolled patients, paired BMD data were available for 123 and 101 patients treated with letrozole and exemestane, respectively, and paired BTM data were available for 175 and 173 patients, respectively. The mean change in lumbar spine BMD was significantly greater for letrozole-treated (-3.2 %) compared to exemestane-treated patients (-1.0 %) (p = 0.0016). Urine N-telopeptide was significantly increased in patients treated with exemestane (p = 0.001) but not letrozole. Two SNPs (rs4870061 and rs9322335) in ESR1 and one SNP (rs10140457) in ESR2 were associated with decreased BMD in letrozole-treated patients. In the exemestane-treated patients, SNPs in ESR1 (Rs2813543) and CYP19A1 (Rs6493497) were associated with decreased bone density. Exemestane had a less negative impact on bone density compared to letrozole, and the effects of AI therapy on bone may be impacted by genetic variants in the ER pathway.

Roy D, Morgan M, Yoo C, et al.
Integrated Bioinformatics, Environmental Epidemiologic and Genomic Approaches to Identify Environmental and Molecular Links between Endometriosis and Breast Cancer.
Int J Mol Sci. 2015; 16(10):25285-322 [PubMed] Free Access to Full Article Related Publications
We present a combined environmental epidemiologic, genomic, and bioinformatics approach to identify: exposure of environmental chemicals with estrogenic activity; epidemiologic association between endocrine disrupting chemical (EDC) and health effects, such as, breast cancer or endometriosis; and gene-EDC interactions and disease associations. Human exposure measurement and modeling confirmed estrogenic activity of three selected class of environmental chemicals, polychlorinated biphenyls (PCBs), bisphenols (BPs), and phthalates. Meta-analysis showed that PCBs exposure, not Bisphenol A (BPA) and phthalates, increased the summary odds ratio for breast cancer and endometriosis. Bioinformatics analysis of gene-EDC interactions and disease associations identified several hundred genes that were altered by exposure to PCBs, phthalate or BPA. EDCs-modified genes in breast neoplasms and endometriosis are part of steroid hormone signaling and inflammation pathways. All three EDCs-PCB 153, phthalates, and BPA influenced five common genes-CYP19A1, EGFR, ESR2, FOS, and IGF1-in breast cancer as well as in endometriosis. These genes are environmentally and estrogen responsive, altered in human breast and uterine tumors and endometriosis lesions, and part of Mitogen Activated Protein Kinase (MAPK) signaling pathways in cancer. Our findings suggest that breast cancer and endometriosis share some common environmental and molecular risk factors.

Hortobagyi GN, Chen D, Piccart M, et al.
Correlative Analysis of Genetic Alterations and Everolimus Benefit in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer: Results From BOLERO-2.
J Clin Oncol. 2016; 34(5):419-26 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To explore the genetic landscape of tumors from patients enrolled on the BOLERO-2 trial to identify potential correlations between genetic alterations and efficacy of everolimus treatment. The BOLERO-2 trial has previously demonstrated that the addition of everolimus to exemestane prolonged progression-free survival by more than twofold in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, advanced breast cancer previously treated with nonsteroidal aromatase inhibitors.
PATIENTS AND METHODS: Next-generation sequencing was used to analyze genetic status of cancer-related genes in 302 archival tumor specimens from patients representative of the BOLERO-2 study population. Correlations between the most common somatic alterations and degree of chromosomal instability, and treatment effect of everolimus were investigated.
RESULTS: Progression-free survival benefit with everolimus was maintained regardless of alteration status of PIK3CA, FGFR1, and CCND1 or the pathways of which they are components. However, quantitative differences in everolimus benefit were observed between patient subgroups defined by the exon-specific mutations in PIK3CA (exon 20 v 9) or by different degrees of chromosomal instability in the tumor tissues.
CONCLUSION: The data from this exploratory analysis suggest that the efficacy of everolimus was largely independent of the most commonly altered genes or pathways in hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. The potential impact of chromosomal instabilities and low-frequency genetic alterations on everolimus efficacy warrants further investigation.

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