Gene Summary

Gene:CYP1A1; cytochrome P450 family 1 subfamily A member 1
Aliases: AHH, AHRR, CP11, CYP1, CYPIA1, P1-450, P450-C, P450DX
Summary:This gene, CYP1A1, 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 its expression is induced by some polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke. The enzyme's endogenous substrate is unknown; however, it is able to metabolize some PAHs to carcinogenic intermediates. The gene has been associated with lung cancer risk. A related family member, CYP1A2, is located approximately 25 kb away from CYP1A1 on chromosome 15. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jan 2016]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:cytochrome P450 1A1
Source:NCBIAccessed: 11 March, 2017


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

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: CYP1A1 (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.

Liu HX, Li J, Ye BG
Correlation between gene polymorphisms of CYP1A1, GSTP1, ERCC2, XRCC1, and XRCC3 and susceptibility to lung cancer.
Genet Mol Res. 2016; 15(4) [PubMed] Related Publications
Lung cancer is a common malignant tumor that is characterized by high morbidity and poor prognosis. Studies suggest that an individual's genetic background affects the risk of developing lung cancer. Therefore, we investigated the relationship between gene polymorphisms and susceptibility to lung cancer. We recruited 308 primary lung cancer patients as subjects and 253 healthy adults as controls. After extraction of DNA from blood samples, gene polymorphisms in CYP1A1, GSTP1, ERCC2, XRCC1, and XRCC3 were investigated by polymerase chain reaction and restriction fragment length polymorphism. The frequencies of the genotypes in both groups were investigated to obtain odds ratios and 95% confidence intervals, and correlation analysis was carried out. The analysis results showed that the following polymorphisms were correlated with susceptibility to lung cancer: rs4646903 in CYP1A1 (P < 0.001), rs1048943 in CYP1A1 (P < 0.001), rs1695 in GSTP1 (P < 0.05), rs13181 in ERCC2 (P < 0.001), and rs25487 in XRCC1 (P < 0.05); no such correlation existed in rs861539 in XRCC3 (P > 0.05). The study revealed that the more high-risk gene polymorphisms a patient carries, the greater the risk of developing lung cancer. Carriers of rs4646903 in CYP1A1, rs1048943 in CYP1A1, rs1695 in GSTP1, rs13181 in ERCC2, and rs25487 in XRCC1 are more likely to develop lung cancer.

Panagopoulos I, Gorunova L, Viset T, Heim S
Gene fusions AHRR-NCOA2, NCOA2-ETV4, ETV4-AHRR, P4HA2-TBCK, and TBCK-P4HA2 resulting from the translocations t(5;8;17)(p15;q13;q21) and t(4;5)(q24;q31) in a soft tissue angiofibroma.
Oncol Rep. 2016; 36(5):2455-2462 [PubMed] Free Access to Full Article Related Publications
We present an angiofibroma of soft tissue with the karyotype 46,XY,t(4;5)(q24;q31),t(5;8;17)(p15;q13;q21)[8]/46,XY,t(1;14)(p31;q32)[2]/46,XY[3]. RNA‑sequencing showed that the t(4;5)(q24;q31) resulted in recombination of the genes TBCK on 4q24 and P4HA2 on 5q31.1 with generation of an in‑frame TBCK‑P4HA2 and the reciprocal but out‑of‑frame P4HA2‑TBCK fusion transcripts. The putative TBCK‑P4HA2 protein would contain the kinase, the rhodanese‑like domain, and the Tre‑2/Bub2/Cdc16 (TBC) domains of TBCK together with the P4HA2 protein which is a component of the prolyl 4‑hydroxylase. The t(5;8;17)(p15;q13;q21) three‑way chromosomal translocation targeted AHRR (on 5p15), NCOA2 (on 8q13), and ETV4 (on 17q21) generating the in‑frame fusions AHRR‑NCOA2 and NCOA2‑ETV4 as well as an out‑of‑frame ETV4‑AHRR transcript. In the AHRR‑NCOA2 protein, the C‑terminal part of AHRR is replaced by the C‑terminal part of NCOA2 which contains two activation domains. The NCOA2‑ETV4 protein would contain the helix‑loop‑helix, PAS_9 and PAS_11, CITED domains, the SRC‑1 domain of NCOA2 and the ETS DNA‑binding domain of ETV4. No fusion gene corresponding to t(1;14)(p31;q32) was found. Our findings indicate that, in spite of the recurrence of AHRR‑NCOA2 in angiofibroma of soft tissue, additional genetic events (or fusion genes) might be required for the development of this tumor.

Karakurt S
Modulatory effects of rutin on the expression of cytochrome P450s and antioxidant enzymes in human hepatoma cells.
Acta Pharm. 2016; 66(4):491-502 [PubMed] Related Publications
Expression of a drug and xenobiotic metabolizing enzymes, cytochrome P450s (CYPs), and antioxidant enzymes can be modulated by various factors. The flavonoid rutin was investigated for its anti-carcinogen and protective effects as well as modulatory action on CYPs and phase II enzymes in human hepatocellular carcinoma cells. Rutin inhibited proliferation of HEPG2 cells in a dose-dependent manner with the IC50 value of 52.7 μmol L-1 and invasion of HEPG2 cells (21.6 %, p = 0.0018) and colony formation of those invaded cells (57.4 %, p < 0.0001). Rutin treatment also significantly increased early/late-stage apoptosis in HEPG2 cells (28.9 %, p < 0.001). Treatment by rutin significantly inhibited protein expressions of cytochrome P450-dependent CYP3A4 (75.3 %, p < 0.0001), elevated CYP1A1 enzymes (1.7-fold, p = 0.0084) and increased protein expressions of antioxidant and phase II reaction catalyzing enzymes, NQO1 (2.42-fold, p < 0.0001) and GSTP1 (2.03-fold, p < 0.0001). Besides, rutin treatment significantly inhibited mRNA expression of CYP3A4 (73.2 %, p=0.0014). Also, CYP1A1, NQO1 and GSTP1 mRNA expressions were significantly increased 2.77-fold (p = 0.029), 4.85- fold (p = 0.0051) and 9.84-fold (p < 0.0001), respectively.

GallegosVargas J, SanchezRoldan J, RonquilloSanchez M, et al.
Gene Expression of CYP1A1 and its Possible Clinical Application in Thyroid Cancer Cases.
Asian Pac J Cancer Prev. 2016; 17(7):3477-82 [PubMed] Related Publications
BACKGROUND: Thyroid cancer is the most common endocrine malignancy, and exact causes remain unknown. The role of CYP450 1A1 (CYP1A1) in cancer initiation and progression has been investigated. The aim of this work was to analyze, for the first time, CYP1A1 gene expression and its relationship with several clinicopathological factors in Mexican patients diagnosed with thyroid cancer.
MATERIALS AND METHODS: Realtime PCR analysis was conducted on 32 sets of thyroid tumors and benign pathologies. Expression levels were tested for correlations with clinical and pathological data. All statistical analysis were performed using GraphPad Prism version 3.0 software.
RESULTS: We found that female gender was associated with thyroid cancer risk (P<0.05). A positive relationship was identified between CYP1A1 mRNA levels and the presence of chronic disease, alcohol use, tumor size, metastasis and an advanced clinical stage (P<0.05).
CONCLUSIONS: The results suggest that CYP1A1 gene expression could be used as a marker for thyroid cancer.

Yaming P, Urs AB, Saxena A, Zuberi M
Roles of CYP1A1 and CYP2E1 Gene Polymorphisms in Oral Submucous Fibrosis.
Asian Pac J Cancer Prev. 2016; 17(7):3335-40 [PubMed] Related Publications
BACKGROUND: Oral submucous fibrosis (OSF) is a precancerous condition with a 4 to13% malignant transformation rate. Related to the habit of areca nut chewing it is mainly prevalent in Southeast Asian countries where the habit of betel quid chewing is frequently practised. On chewing, alkaloids and polyphenols are released which undergo nitrosation and give rise to Nnitrosamines which are cytotoxic agents. CYP450 is a microsomal enzyme group which metabolizes various endogenous and exogenous chemicals including those released by areca nut chewing. CYP1A1 plays a central role in metabolic activation of these xenobiotics, whereas CYP2E1 metabolizes nitrosamines and tannins. Polymorphisms in genes that code for these enzymes may alter their expression or function and may therefore affect an individuals susceptibility regarding OSF and oral cancer. The present study was therefore undertaken to investigate the association of polymorphisms in CYP1A1 m2 and CYP2E1 (RsaI/PstI) sites with risk of OSF among areca nut chewers in the Northern India population. A total of 95 histopathologically confirmed cases of OSF with history of areca nut chewing not less than 1 year and 80, age and sex matched controls without any clinical signs and symptoms of OSF with areca nut chewing habit not less than 1 year were enrolled. DNA was extracted from peripheral blood samples and polymorphisms were analyzed by PCRRFLP method. Gene polymorphism of CYP1A1 at NcoI site was observed to be significantly higher (p = 0.016) in cases of OSF when compared to controls. Association of CYP1A1 gene polymorphism at NcoI site and the risk of OSF (Odd's Ratio = 2.275) was also observed to be significant. However, no such association was observed for the CYP2E1 gene polymorphism (Odd's Ratio = 0.815). Our results suggest that the CYP1A1 gene polymorphism at the NcoI site confers an increased risk for OSF.

Salimi S, Sajadian M, Khodamian M, et al.
Combination effect of cytochrome P450 1A1 gene polymorphisms on uterine leiomyoma: A case-control study.
Bosn J Basic Med Sci. 2016; 16(3):209-14 [PubMed] Free Access to Full Article Related Publications
Uterine leiomyoma (UL) is an estrogen-dependent neoplasm of the uterus, and estrogen metabolizing enzymes affect its progression. This study aimed to evaluate the association between two single-nucleotide polymorphisms of cytochrome P450 1A1 (CYP1A1) gene and UL risk. The study consisted of 105 patients with UL and 112 healthy women as controls. Ile462Val (A/G) and Asp449Asp (T/C) polymorphisms of CYP1A1 gene were analyzed by DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism methods, respectively. The findings indicated no association between Ile462Val (A/G) and Asp449Asp (T/C) polymorphisms of CYP1A1 gene and UL (p < 0.05). However, the combination effect of TT/AG genotypes of the Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms was associated with 4.3-fold higher risk of UL. In addition, haplotype analysis revealed that TG haplotype of the Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms could increase the UL risk nearly 4.9-fold. Asp449Asp (T/C) and Ile462Val (A/G) polymorphisms of CYP1A1 gene were not associated with UL susceptibility; however, the combination of the TT/AG genotypes and TG haplotype could increase the UL risk.

Abo-Hashem EM, El-Emshaty WM, Farag Rel S, et al.
Genetic Polymorphisms of Cytochrome P4501A1 (CYP1A1) and Glutathione S-Transferase P1 (GSTP1) and Risk of Hepatocellular Carcinoma Among Chronic Hepatitis C Patients in Egypt.
Biochem Genet. 2016; 54(5):696-713 [PubMed] Related Publications
Cytochrome P450 1A1 (CYP1A1) and Glutathione S-transferase P1 (GSTP1) genes are involved in the metabolism of many carcinogens. Polymorphisms in these genes with altered enzyme activity have been reported. The present study evaluated the synergistic effect between CYP1A1 and GSTP1 gene polymorphisms and smoking on development of HCV-related liver disease and hepatocellular carcinoma (HCC). The patients group comprised 40 patients with HCC and 40 patients with liver cirrhosis. The control group comprised 40 healthy subjects having no history of malignancy. The genetic polymorphisms were studied using polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) technique on blood samples. The number of current or former smoker among HCC and cirrhotic patients as well as the median Pack/year of cigarette smoked were significantly higher in HCC and liver cirrhotic patients than in control group. Subjects with CYP1A1 gene variants (m1 and m3) had no significant risk to develop cirrhosis or HCC compared to control group. Individuals carrying the Ile/Val genotype of GSTP1 had a significant increased risk of HCC (OR of 2.2, 95 % CI 1.143-4.261) and had larger tumor size. No significant risk was observed on combining both genes variants or on combining smoking with variants of both genes. In conclusion, the GSTP1 Ile/Val genotype and Val allele are associated with an increased risk of HCC. CYP1A1 and GSTP1 genes variants interaction did not increase the risk of HCC.

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.

Peddireddy V, Badabagni SP, Gundimeda SD, et al.
Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of non-small cell lung cancer in Andhra Pradesh region of South India.
Eur J Med Res. 2016; 21:17 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Lung cancer is one of the most preventable causes of death globally both in developed and developing countries. Although it is well established that smokers develop lung cancer, there are some smokers who are free from the disease risk. The predisposition to lung cancer is attributed to genetic polymorphisms in xenobiotic metabolizing genes. Reports on assessment of xenobiotic metabolizing genes like Cytochrome P 450 1A1 (CYP1A1), Glutathione -S -transferase M1 (GSTM1) and T1 (GSTT1) polymorphisms from India are meagre, and reports from Andhra Pradesh are lacking.
METHODS AND RESULTS: Assessment of polymorphisms in CYP1A1, GSTM1 and GSTT1 in NSCLC patients and healthy individuals specific to population of Andhra Pradesh, a South Indian state was attempted by multiplex PCR and RFLP, and this is the first study which tried to correlate oxidative stress with the polymorphisms in xenobiotic metabolizing genes. Results showed that CYP1A1 m1 'CC' genotype was significantly associated with lung cancer susceptibility with a 2.3-fold risk, CYP1A1 m2 'AG' gene polymorphisms with 8.8-fold risk and GSTT1 (-/-) genotype demonstrated a twofold risk of disease susceptibility.
CONCLUSIONS: A combined role of genetic polymorphisms and smoking status can be attributed for the cause of lung cancer. Further, the association between oxidative stress and genetic polymorphisms showed a correlation between GSTT1 and super oxide dismutase activity; CYP1A1 m1, m2 and GSTT1 with glutathione peroxidase activity; CYP1A1 m1 and GSTM1 with melondialdehyde levels; and CYP1A1 m1 and GSTT1 with 8-oxo-7,8-dihydro-2'-deoxyguanosine. A higher risk of lung cancer seems to be associated with combined gene polymorphisms of phase I and phase II enzymes than that ascribed to single gene polymorphism.

Stanford EA, Wang Z, Novikov O, et al.
The role of the aryl hydrocarbon receptor in the development of cells with the molecular and functional characteristics of cancer stem-like cells.
BMC Biol. 2016; 14:20 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Self-renewing, chemoresistant breast cancer stem cells are believed to contribute significantly to cancer invasion, migration and patient relapse. Therefore, the identification of signaling pathways that regulate the acquisition of stem-like qualities is an important step towards understanding why patients relapse and towards development of novel therapeutics that specifically target cancer stem cell vulnerabilities. Recent studies identified a role for the aryl hydrocarbon receptor (AHR), an environmental carcinogen receptor implicated in cancer initiation, in normal tissue-specific stem cell self-renewal. These studies inspired the hypothesis that the AHR plays a role in the acquisition of cancer stem cell-like qualities.
RESULTS: To test this hypothesis, AHR activity in Hs578T triple negative and SUM149 inflammatory breast cancer cells were modulated with AHR ligands, shRNA or AHR-specific inhibitors, and phenotypic, genomic and functional stem cell-associated characteristics were evaluated. The data demonstrate that (1) ALDH(high) cells express elevated levels of Ahr and Cyp1b1 and Cyp1a1, AHR-driven genes, (2) AHR knockdown reduces ALDH activity by 80%, (3) AHR hyper-activation with several ligands, including environmental ligands, significantly increases ALDH1 activity, expression of stem cell- and invasion/migration-associated genes, and accelerates cell migration, (4) a significant correlation between Ahr or Cyp1b1 expression (as a surrogate marker for AHR activity) and expression of stem cell- and invasion/migration-associated gene sets is seen with genomic data obtained from 79 human breast cancer cell lines and over 1,850 primary human breast cancers, (5) the AHR interacts directly with Sox2, a master regulator of self-renewal; AHR ligands increase this interaction and nuclear SOX2 translocation, (6) AHR knockdown inhibits tumorsphere formation in low adherence conditions, (7) AHR inhibition blocks the rapid migration of ALDH(high) cells and reduces ALDH(high) cell chemoresistance, (8) ALDH(high) cells are highly efficient at initiating tumors in orthotopic xenografts, and (9) AHR knockdown inhibits tumor initiation and reduces tumor Aldh1a1, Sox2, and Cyp1b1 expression in vivo.
CONCLUSIONS: These data suggest that the AHR plays an important role in development of cells with cancer stem cell-like qualities and that environmental AHR ligands may exacerbate breast cancer by enhancing expression of these properties.

Ren L, Thompson JD, Cheung M, et al.
Selective suppression of the human aryl hydrocarbon receptor function can be mediated through binding interference at the C-terminal half of the receptor.
Biochem Pharmacol. 2016; 107:91-100 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
The human aryl hydrocarbon receptor is a cytosolic signaling molecule which affects immune response and aberrant cell growth. Canonical signaling of the receptor requires the recruitment of coactivators to the promoter region to remodel local chromatin structure. We predicted that interference of this recruitment would block the aryl hydrocarbon receptor function. To prove that, we employed phage display to identify nine peptides of twelve-amino-acid in length which target the C-terminal half of the human aryl hydrocarbon receptor, including the region where coactivators bind. Eight 12mer peptides, in the form of GFP fusion, suppressed the ligand-dependent transcription of six AHR target genes (cyp1a1, cyp1a2, cyp1b1, ugt1a1, nqo1, and ahrr) in different patterns in Hep3B cells, whereas the AHR antagonist CH-223191 suppressed all these target genes similarly. Three of the 12mer peptides (namely 11-3, 1-7, and 7-3) suppressed the 3MC-induced, CYP1A1-dependent EROD activity and the ROS production caused by benzo[a]pyrene. These 12mer peptides suppressed the AHR function synergistically with CH-223191. In conclusion, we provide evidence that targeting the C-terminal half of the human aryl hydrocarbon receptor is a viable, new approach to selectively block the receptor function.

Bag A, Jyala NS, Bag N
Cytochrome P450 1A1 genetic polymorphisms as cancer biomarkers.
Indian J Cancer. 2015 Oct-Dec; 52(4):479-89 [PubMed] Related Publications
Phase I metabolic enzyme CYP1A1 plays an important role in xenobiotics metabolism and has been extensively studied as a cancer risk biomarker. CYP1A1 is polymorphic and its four variants, e.g., CYP1A1* 2 A, CYP1A1* 2C, CYP1A1* 3 and CYP1A1* 4 with trivial names m1, m2, m3, and m4 respectively, are most commonly studied for cancer link. Gene- gene interaction studies combining polymorphisms of this enzyme with those of phase II detoxifying enzymes, especially glutathione S- transferases (GSTs) revealed greater risk for cancer susceptibility. Variants of CYP1A1 have also been found to be associated with chemotherapeutic adverse- effects. Results of these studies, however, remained largely contradictory mainly because of lack of statistical power due to involvement of small sample size. Strongly powered experimental designs involving gene- gene, gene- environment interactions are required in order to validate CYP1A1 as reliable cancer- biomarker.

Tan YH, Sidik SM, Syed Husain SN, et al.
CYP1A1 MspI Polymorphism and Cervical Carcinoma Risk in the Multi-Ethnic Population of Malaysia: a Case-Control Study.
Asian Pac J Cancer Prev. 2016; 17(1):57-64 [PubMed] Related Publications
BACKGROUND: Tobacco smoking is considered a risk factor for cervical cancer development due to the presence of tobacco based carcinogenic metabolites in cervical cells of female smokers. In this study, we investigated the role of the T3801C (MspI) polymorphism of CYP1A1, a gene encoding an enzyme necessary for the initiation of tobacco based carcinogen metabolism, on cervical cancer risk. The T to C substitution may alter CYP1A1 activities, potentially elevating cervical cancer risk. Since results of gene-disease association studies vary according to the study population, the multi-ethnic population of Malaysia provides an excellent representative cohort for identifying and comparing the cervical cancer risk among the 3 major ethnics in Southeast Asia in relation to CYP1A1 MspI polymorphism.
MATERIALS AND METHODS: A total of 195 Thin Prep Pap smear samples from HPV negative and cancer free females were randomly selected as controls while 106 formalin fixed paraffin embedded samples from females with invasive cervical cancer were randomly selected for the cases group. The polymorphisms were identified using restriction fragment length polymorphism (RFLP) PCR.
RESULTS: We found no significant associations between CYP1A1 MspI polymorphism and cervical cancer in the general Malaysian female population. However, upon ethnic stratification, the variant C/C genotype was significantly associated with a 4.66-fold increase in cervical cancer risk in Malay females (95% CI= 1.21-17.9; p=0.03). No significant association was observed in the Chinese and Indian females. Additionally, there were no significant associations in the dominant model and allele frequency model analysis in both the general and ethnically stratified female population of Malaysia.
CONCLUSIONS: Our findings suggest that the C/C genotype of CYP1A1 MspI polymorphism is associated with the development of cervical carcinoma in the Malay females of Malaysia.

Amrani I, Bulatova N, Awidi A, et al.
Lack of Association between CYP1A1 M2 and M4 Polymorphisms and Breast Carcinoma in Jordanian Women: a Case-Control Study.
Asian Pac J Cancer Prev. 2016; 17(1):387-93 [PubMed] Related Publications
BACKGROUND: CYP1A1 is a candidate gene for low-penetrance breast cancer susceptibility, as it plays an important role in the metabolism of carcinogens and estrogens.
PURPOSE: The objective of this study was to assess the association between M2 (A2455G, Ile462Val) and M4 (C2453A, Thr461Asn) polymorphisms in CYP1A1 and breast cancer risk among Jordanian women and in subgroups stratified by menopausal status and smoking history.
MATERIALS AND METHODS: Blood samples were collected from 112 breast cancer female patients and 115 age-matched controls who underwent breast cancer screening with imaging and showed negative results (BI- RADS I or BI-RADS II). Genotyping was performed using the PCR-RFLP technique.
RESULTS: No statistically significant overall association was found between breast cancer risk and CYP1A1 M2 genotypes (p-value = 0.55; OR = 0.77; 95% CI= 0.32 - 1.83) nor with the M4 polymorphism (p-value= 0.95; OR= 0.95; 95% CI= 0.51- 1.88). Analysis of subgroups defined by menopausal status or smoking history also revealed no association with these polymorphisms. Furthermore, the four identified haplotypes (AC; AA; GC and GA) were equally distributed among cases and controls, and haplotype analysis showed a strong linkage disequilibrium of both studied loci in either cases or controls (D'=1).
CONCLUSIONS: Based on the study results, CYP1A1 M2 and M4 polymorphisms do not seem to play a major role in breast cancer risk among Jordanian females.

Naushad SM, Ramaiah MJ, Pavithrakumari M, et al.
Artificial neural network-based exploration of gene-nutrient interactions in folate and xenobiotic metabolic pathways that modulate susceptibility to breast cancer.
Gene. 2016; 580(2):159-68 [PubMed] Related Publications
In the current study, an artificial neural network (ANN)-based breast cancer prediction model was developed from the data of folate and xenobiotic pathway genetic polymorphisms along with the nutritional and demographic variables to investigate how micronutrients modulate susceptibility to breast cancer. The developed ANN model explained 94.2% variability in breast cancer prediction. Fixed effect models of folate (400 μg/day) and B12 (6 μg/day) showed 33.3% and 11.3% risk reduction, respectively. Multifactor dimensionality reduction analysis showed the following interactions in responders to folate: RFC1 G80A × MTHFR C677T (primary), COMT H108L × CYP1A1 m2 (secondary), MTR A2756G (tertiary). The interactions among responders to B12 were RFC1G80A × cSHMT C1420T and CYP1A1 m2 × CYP1A1 m4. ANN simulations revealed that increased folate might restore ER and PR expression and reduce the promoter CpG island methylation of extra cellular superoxide dismutase and BRCA1. Dietary intake of folate appears to confer protection against breast cancer through its modulating effects on ER and PR expression and methylation of EC-SOD and BRCA1.

Xie YQ, Chen JM, Liu Y
Interaction of the CYP1A1 gene polymorphism and smoking in non-small cell lung cancer susceptibility.
Genet Mol Res. 2016; 14(4):19411-7 [PubMed] Related Publications
Many studies have shown that genetic factors, environmental factors, and bad living habits, especially smoking, are risk factors for lung cancer. However, not all smokers develop lung cancer, which may be related to different genetic backgrounds. Currently, most research has investigated the GSTM1, XRCC1, XRCC3, CYP2D6, and C188T genes. Little research has been done on the cytochrome P450 (CYP) 1A1 gene, and results have varied. In addition, no results have been reported on the interactive effects of smoking and the CYP1A1 gene on lung cancer development. We used polymerase chain reaction restriction fragment length polymorphism to detect the CYP1A1 genotype, and investigate the effects of the CYP1A1 gene deletion and smoking alone, and in combination, on non-small cell lung cancer susceptibility. We enrolled 150 non-small cell lung cancer patients and 150 healthy control subjects. Subjects' smoking habits and CYP1A1 gene polymorphism were analyzed to investigate their role in the occurrence of lung cancer. The CYP1A1 gene deletion was found in 73.3% of non-small cell lung cancer patients and 20.0% of healthy subjects. The OR value was 2.28 (P < 0.05). Among smoking subjects, 77.8% exhibited non-small cell lung cancer, significantly higher than the 27.3% in non-smokers (P < 0.05). The OR value for the interaction of smoking and CYP1A1 gene deletion was 5.60, larger than the product of their individual OR values. The CYP1A1 gene deletion is a lung cancer risk factor, and interacts with smoking in non-small cell lung cancer development.

Zeng M, Lv Y, Wang HF, et al.
Correlation of CYP1A1 and GSTM1 gene polymorphisms and environmental factors to familial aggregation of esophageal cancer among the Kazakh ethnic group in Xinjiang.
Genet Mol Res. 2015; 14(4):19102-9 [PubMed] Related Publications
This study aimed to investigate the correlation of CYP1A1 and GSTM1 gene polymorphisms and environmental factors to familial aggregation of esophageal cancer (EC) among the Kazakh ethnic group in Xinjiang. CYP1A1 and GSTM1 gene polymorphisms were detected using peripheral blood from 86 subjects belonging to families with EC and 82 control subjects. Additionally, a questionnaire survey was conducted to ascertain environmental risk factors. Combined effects of CYP1A1 and GSTM1 gene polymorphisms and environmental factors in familial aggregation of EC were evaluated. Distribution frequencies of CYP1A1 MspI and GSTM1 genotypes between EC and control families showed significant differences (P = 0.002, P = 0.001). Contribution of interaction between CYP1A1 MspI mutant and GSTM1 deletion polymorphisms to familial aggregation of EC was significant, with OR = 3.571 (95%CI = 1.738-3.346). Logistic multivariate analysis indicated that familial aggregation of EC is correlated with 3 factors: drinking water, intake of fresh vegetables and fruits, and CYP1A1 MspI polymorphism (P = 0.005, P = 0.013, and P = 0.001). Sufficient intake of fresh vegetables and fruits (OR = 0.278, 95%CI = 0.137-0.551) protected against familial aggregation of EC, while drinking water (OR = 3.468, 95%CI = 1.562-6.551) and CYP1A1 MspI polymorphism (OR = 2.732, 95%CI = 1.741-3.886) were the risk factors. In conclusion, CYP1A1 and GSTM1 gene polymorphisms affect familial aggregation of EC among the Kazakh ethnic group in Xinjiang. River water intake and CYP1A1 MspI polymorphism were risk factors that likely contributed to high incidence of EC among families.

Kleine JP, Camargo-Kosugi CM, Carvalho CV, et al.
Analysis of CYP1A1 and COMT polymorphisms in women with cervical cancer.
Genet Mol Res. 2015; 14(4):18965-73 [PubMed] Related Publications
The aim of this case-control study was to obtain a comprehensive panel of genetic polymorphisms present only in genes (cytochrome P-450 1A1--CYP1A1 and catechol-O-methyl transferase--COMT) within the metabolic pathway of sex steroids and determine their possible associations with the presence or absence of cervical cancer. Genotypes of 222 women were analyzed: a) 81 with cancer of the cervix treated at the Cancer Hospital Alfredo Abram, between June 2012 and May 2013, with diagnosis confirmed surgically and/or through histomorphological examination; and b) 141 healthy women who assisted at the Endocrine Gynecology and Climacteric Ambulatory, Department of Gynecology, UNIFESP-EPM. These polymorphisms were detected by polymerase chain reaction amplification-restriction fragment length polymorphism analysis and visualized on 3% agarose gels stained with ethidium bromide. We found a significant association between the frequency of the CYP1A1 polymorphism and the development of cervical cancer. A statistical difference was observed between patient and control groups for CYP1A1 polymorphism genotype distributions (P < 0.05). However, no significant differences were found in the COMT gene polymorphism genotype distributions between the patient and control groups (P > 0.05) or between other risk variables analyzed. The CYP1A1 gene involved in the metabolic pathway of sex steroids might influence the emergence of pathological conditions such as cervical cancer in women who carry a mutated allele, and result in 1.80 and 13.46 times increased risk for women with heterozygous or homozygous mutated genotypes, respectively.

Aşık E, Aslan TN, Volkan M, Güray NT
2-Amino-2-deoxy-glucose conjugated cobalt ferrite magnetic nanoparticle (2DG-MNP) as a targeting agent for breast cancer cells.
Environ Toxicol Pharmacol. 2016; 41:272-8 [PubMed] Related Publications
In this study, 2-amino-2-deoxy-glucose (2DG) was conjugated to COOH modified cobalt ferrite magnetic nanoparticles (COOH-MNPs), which were designed to target tumor cells as a potential targetable drug/gene delivery agent for cancer treatment. According to our results, it is apparent that, 2DG labeled MNPs were internalized more efficiently than COOH-MNPs under the same conditions in all cell types (MDA-MB-231 and MCF-7 cancer and MCF-10A normal breast cells) (p<0.001). Moreover, the highest amount of uptake was observed in MDA-MB-231, followed by MCF-7 and normal MCF-10A cells for both MNPs. The apoptotic effects of 2DG-MNPs were further evaluated, and it was found that apoptosis was not induced at low concentrations of 2DG-MNPs in all cell types, whereas dramatic cell death was observed at higher concentrations. In addition, the gene expression levels of four drug-metabolizing enzymes, two Phase I (CYP1A1, CYP1B1) and two Phase II (GSTM3, GSTZ1) were also increased with the high concentrations of 2DG-MNPs.

Romagnolo DF, Papoutsis AJ, Laukaitis C, Selmin OI
Constitutive expression of AhR and BRCA-1 promoter CpG hypermethylation as biomarkers of ERα-negative breast tumorigenesis.
BMC Cancer. 2015; 15:1026 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
BACKGROUND: Only 5-10% of breast cancer cases is linked to germline mutations in the BRCA-1 gene and occurs early in life. Conversely, sporadic breast tumors, which represent 90-95% of breast malignancies, have lower BRCA-1 expression, but not mutated BRCA-1 gene, and tend to occur later in life in combination with other genetic alterations and/or environmental exposures. The latter may include environmental and dietary factors that activate the aromatic hydrocarbon receptor (AhR). Therefore, understanding if changes in expression and/or activation of the AhR are associated with somatic inactivation of the BRCA-1 gene may provide clues for breast cancer therapy.
METHODS: We evaluated Brca-1 CpG promoter methylation and expression in mammary tumors induced in Sprague-Dawley rats with the AhR agonist and mammary carcinogen 7,12-dimethyl-benzo(a)anthracene (DMBA). Also, we tested in human estrogen receptor (ER)α-negative sporadic UACC-3199 and ERα-positive MCF-7 breast cancer cells carrying respectively, hyper- and hypomethylated BRCA-1 gene, if the treatment with the AhR antagonist α-naphthoflavone (αNF) modulated BRCA-1 and ERα expression. Finally, we examined the association between expression of AhR and BRCA-1 promoter CpG methylation in human triple-negative (TNBC), luminal-A (LUM-A), LUM-B, and epidermal growth factor receptor-2 (HER-2)-positive breast tumor samples.
RESULTS: Mammary tumors induced with DMBA had reduced BRCA-1 and ERα expression; higher Brca-1 promoter CpG methylation; increased expression of Ahr and its downstream target Cyp1b1; and higher proliferation markers Ccnd1 (cyclin D1) and Cdk4. In human UACC-3199 cells, low BRCA-1 was paralleled by constitutive high AhR expression; the treatment with αNF rescued BRCA-1 and ERα, while enhancing preferential expression of CYP1A1 compared to CYP1B1. Conversely, in MCF-7 cells, αNF antagonized estradiol-dependent activation of BRCA-1 without effects on expression of ERα. TNBC exhibited increased basal AhR and BRCA-1 promoter CpG methylation compared to LUM-A, LUM-B, and HER-2-positive breast tumors.
CONCLUSIONS: Constitutive AhR expression coupled to BRCA-1 promoter CpG hypermethylation may be predictive markers of ERα-negative breast tumor development. Regimens based on selected AhR modulators (SAhRMs) may be useful for therapy against ERα-negative tumors, and possibly, TNBC with increased AhR and hypermethylated BRCA-1 gene.

Li L, Li JG, Liu CY, Ding YJ
Effect of CYP1A1 and GSTM1 genetic polymorphisms on bone tumor susceptibility.
Genet Mol Res. 2015; 14(4):16600-7 [PubMed] Related Publications
Tumor gene polymorphisms are often associated with individual susceptibility to genetic diseases. Cytochrome P4501A1 (CYP1A1) and glutathione S-transferase mu 1 (GSTM1) gene polymorphisms are closely related to the susceptibility of the body to chemical carcinogens in the environment. Therefore, we explored the relationship between CYP1A1 and GSTM1 gene polymorphisms and susceptibility to bone tumors. Multiplex-polymerase chain reaction (PCR), allelic-specific PCR, and PCR-restriction fragment length polymorphism techniques were used to analyze CYP1A1 and GSTM1 gene polymorphisms in 52 bone tumor patients and 100 healthy subjects. The allelic variation frequency of the CYP1A1 gene at exon 7 (Ile 462 Val) in bone tumor patients was 0.462, which was significantly higher than that in the normal controls (0.223). The frequency of the absence of the GSTM1 homozygous genotype in the patients (0.65) was also markedly higher than that in the control group (0.41). Subjects with CYP1A1 Val/Val homozygous mutations and absence of the GSTM1 homozygous genotype were at markedly increased risk of developing bone tumors [ORs 4.15 (95%CI: 1.268-13.30) and 2.35 (95%CI: 1.15-4.85), respectively]. The OR for the combined effect of the CYP1A1 and GSTM1 gene polymorphisms was 8.55 (95%CI: 1.75-41.50). CYP1A1 and GSTM1 polymorphisms are genetic risk factors in patients with bone tumors, and the allelic variation of these genes increases the risk of bone tumor occurrence.

Fasanelli F, Baglietto L, Ponzi E, et al.
Hypomethylation of smoking-related genes is associated with future lung cancer in four prospective cohorts.
Nat Commun. 2015; 6:10192 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
DNA hypomethylation in certain genes is associated with tobacco exposure but it is unknown whether these methylation changes translate into increased lung cancer risk. In an epigenome-wide study of DNA from pre-diagnostic blood samples from 132 case-control pairs in the NOWAC cohort, we observe that the most significant associations with lung cancer risk are for cg05575921 in AHRR (OR for 1 s.d.=0.37, 95% CI: 0.31-0.54, P-value=3.3 × 10(-11)) and cg03636183 in F2RL3 (OR for 1 s.d.=0.40, 95% CI: 0.31-0.56, P-value=3.9 × 10(-10)), previously shown to be strongly hypomethylated in smokers. These associations remain significant after adjustment for smoking and are confirmed in additional 664 case-control pairs tightly matched for smoking from the MCCS, NSHDS and EPIC HD cohorts. The replication and mediation analyses suggest that residual confounding is unlikely to explain the observed associations and that hypomethylation of these CpG sites may mediate the effect of tobacco on lung cancer risk.

Bodduluru LN, Kasala ER, Madhana RM, et al.
Naringenin ameliorates inflammation and cell proliferation in benzo(a)pyrene induced pulmonary carcinogenesis by modulating CYP1A1, NFκB and PCNA expression.
Int Immunopharmacol. 2016; 30:102-10 [PubMed] Related Publications
Lung cancer is the major cause of cancer-related mortality and is a growing economic burden worldwide. Chemoprevention has emerged as a very effective preventive measure against carcinogenesis and several bioactive compounds in diet have shown their cancer curative potential on lung cancer. Naringenin (NRG), a predominant flavanone found in citrus fruits has been reported to possess anti-oxidative, anti-inflammatory and anti-proliferative activity in a wide variety of cancer. The aim of the present study is to divulge the chemopreventive nature of NRG against benzo(a)pyrene (B[a]P) induced lung carcinogenesis in Swiss albino mice. Administration of B[a]P (50mg/kg, p.o.) to mice resulted in increased lipid peroxidation (LPO), proinflammatory cytokines (TNF-α, IL-6 and IL-1β) with subsequent decrease in activities of tissue enzymic antioxidants (SOD, CAT, GPx, GR, GST) and non-enzymic antioxidants (GSH and Vit-C). Treatment with NRG (50mg/kg body weight) significantly counteracted all these alterations thereby showing potent anti-cancer effect in lung cancer. Moreover, assessment of protein expression by immunoblotting and mRNA expression by RT-PCR revealed that NRG treatment effectively negates B[a]P-induced upregulated expression of CYP1A1, PCNA and NF-κB. Further, the antiproliferative effect of NRG was confirmed by histopathological analysis and PCNA immunostaining in B[a]P induced mice which showed increased PCNA expression that was restored upon NRG administration. Overall, these findings substantiate the chemopreventive potential of NRG against chemically induced lung cancer in mice.

He X, Feng S
Role of Metabolic Enzymes P450 (CYP) on Activating Procarcinogen and their Polymorphisms on the Risk of Cancers.
Curr Drug Metab. 2015; 16(10):850-63 [PubMed] Related Publications
Cytochrome P450 (CYP450) enzymes are the most important metabolizing enzyme family exists among all organs. Apart from their role in the deactivation of most endogenous compounds and xenobiotics, they also mediate most procarcinogens oxidation to ultimate carcinogens. There are several modes of CYP450s activation of procarcinogens. 1) Formation of epoxide and diol-epoxides intermediates, such as CYP1A1 and CYP1B1 mediates PAHs oxidation to epoxide intermediates; 2) Formation of diazonium ions, such as CYP2A6, CYP2A13 and CYP2E1 mediates activation of most nitrosamines to unstable metabolites, which can rearrange to give diazonium ions. 3) Formation of reactive semiquinones and quinines, such as CYP1A1 and CYP1B1 transformation of estradiol to catechol estrogens, subsequently formation semiquinones; 4) Formation of toxic O-esterification, such as CYP1A1 and CYP1A2 metabolizes PhIP to N(2)-acetoxy-PhIP and N(2)-sulfonyloxy-PhIP, which are carcinogenic metabolites. 5) Formation of free radical, such as CYP2E1 is involved in activation tetrachloromethane to free radicals. While for CYP2B6 and CYP2D6, only a minor role has been found in procarcinogens activation. In addition, as the gene polymorphisms reflected, the polymorphisms of CYP1A1 (-3801T/C and -4889A/G), CYP1A2 (- 163C/A and -2467T/delT), CYP1B1 (-48G/C, -119G/T and -432G/C), CYP2E1 (-1293G/C and -1053 C/T) have been associated with an increased risk of lung cancer. The polymorphisms CYP1A1 (-3801T/C and -4889A/G), and CYP2E1 (PstI/Rsa and 9-bp insertion) have an association with higher risk colon cancers, whereas CYP1A2 (-163C/A and -3860G/A) polymorphism is found to be among the protective factors. The polymorphisms CYP1A1 (-3801T/C and -4889A/G), CYP1B1 -432G/C, CYP2B6 (-516G/T and -785A/G) may increase the risk of breast cancer. In conclusion, CYP1A1, CYP1A2, CYP1B1, CYP2A6, and CYP2E1 are responsible for most of the procarcinogens activation, and their gene polymorphisms are associated with the risk of cancers.

Terashima J, Goto S, Hattori H, et al.
CYP1A1 and CYP1A2 expression levels are differentially regulated in three-dimensional spheroids of liver cancer cells compared to two-dimensional monolayer cultures.
Drug Metab Pharmacokinet. 2015; 30(6):434-40 [PubMed] Related Publications
Compared to two-dimensional (2D) monolayer cultures, three-dimensional (3D) tumor cell culture models are thought to be structurally more similar to the in vivo tumor microenvironment. We investigated the regulation of the expression of genes encoding the drug-metabolizing enzymes CYP1A1 and CYP1A2 in 3D spheroids comprised of cells of the human hepatocellular carcinoma cell JHH1, Huh7, and HepG2. Expression of CYP1A1 and CYP1A2 in the spheroids was higher than that in 2D cultured cells. Expression of CYP1A1 and CYP1A2 is regulated by aryl hydrocarbon receptor (AhR) in 2D cultured cells. Knockdown of AhR in spheroids suppressed CYP1A1 expression; however, CYP1A2 expression levels remained unchanged. Moreover, we found that pregnane X receptor (PXR) likely regulated CYP1A2 expression in JHH1, HepG2, and Huh7 spheroids and that CYP1A1 expression in JHH1 and Huh7 3D spheroids is regulated not only by AhR but also by PXR. It is well known that gene expression levels are different between 3D spheroids and 2D monolayer cultured cells, and our results indicate that the regulation of gene expression also varies between the two culture conditions. Taken together, these results underlie a novel finding regarding the regulation of drug-metabolizing enzyme expression in liver cancer cells growing as 3D spheroids.

Zhu Y, He W, Gao X, et al.
Resveratrol overcomes gefitinib resistance by increasing the intracellular gefitinib concentration and triggering apoptosis, autophagy and senescence in PC9/G NSCLC cells.
Sci Rep. 2015; 5:17730 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Gefitinib (Gef) provides clinical benefits to non-small cell lung cancer (NSCLC) patients with activating EGFR mutations. However, acquired resistance (AR) is a major obstacle to effective Gef therapy. This study demonstrated that resveratrol (Res) could synergize with Gef to inhibit the proliferation of Gef-resistant NSCLC cells. The underlying mechanisms of synergism were investigated, and the results showed that cotreatment with Gef and Res could inhibit EGFR phosphorylation by increasing intracellular Gef accumulation through the impairment of Gef elimination from PC9/G cells. Consistently, CYP1A1 and ABCG2 expression were inhibited. Meanwhile, the cotreatment significantly induced cell apoptosis, autophagy, cell cycle arrest and senescence accompanied by increased expression of cleaved caspase-3, LC3B-II, p53 and p21. Further studies revealed that autophagy inhibition enhanced apoptosis and abrogated senescence while apoptosis inhibition had no notable effect on cell autophagy and senescence during cotreatment with Gef and Res. These results indicated that in addition to apoptosis, senescence promoted by autophagy contributes to the antiproliferation effect of combined Gef and Res on PC9/G cells. In conclusion, combined treatment with Gef and Res may represent a rational strategy to overcome AR in NSCLC cells.

Stavrinou P, Mavrogiorgou MC, Polyzoidis K, et al.
Expression Profile of Genes Related to Drug Metabolism in Human Brain Tumors.
PLoS One. 2015; 10(11):e0143285 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
BACKGROUND: Endogenous and exogenous compounds as well as carcinogens are metabolized and detoxified by phase I and II enzymes, the activity of which could be crucial to the inactivation and hence susceptibility to carcinogenic factors. The expression of these enzymes in human brain tumor tissue has not been investigated sufficiently. We studied the association between tumor pathology and the expression profile of seven phase I and II drug metabolizing genes (CYP1A1, CYP1B1, ALDH3A1, AOX1, GSTP1, GSTT1 and GSTM3) and some of their proteins.
METHODS: Using qRT-PCR and western blotting analysis the gene and protein expression in a cohort of 77 tumors were investigated. The major tumor subtypes were meningioma, astrocytoma and brain metastases, -the later all adenocarcinomas from a lung primary.
RESULTS: Meningeal tumors showed higher expression levels for AOX1, CYP1B1, GSTM3 and GSTP1. For AOX1, GSTM and GSTP1 this could be verified on a protein level as well. A negative correlation between the WHO degree of malignancy and the strength of expression was identified on both transcriptional and translational level for AOX1, GSTM3 and GSTP1, although the results could have been biased by the prevalence of meningiomas and glioblastomas in the inevitably bipolar distribution of the WHO grades. A correlation between the gene expression and the protein product was observed for AOX1, GSTP1 and GSTM3 in astrocytomas.
CONCLUSIONS: The various CNS tumors show different patterns of drug metabolizing gene expression. Our results suggest that the most important factor governing the expression of these enzymes is the histological subtype and to a far lesser extent the degree of malignancy itself.

Zeng W, Li Y, Lu E, Ma M
CYP1A1 rs1048943 and rs4646903 polymorphisms associated with laryngeal cancer susceptibility among Asian populations: a meta-analysis.
J Cell Mol Med. 2016; 20(2):287-93 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Many studies have investigated the association between CYP1A1 rs1048943 and rs4646903 polymorphisms and laryngeal cancer risk, but their results have been inconsistent. The PubMed and CNKI were searched for case-control studies published up to 01 July 2015. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta-analysis, we assessed 10 published studies involving comprising 748 laryngeal cancer cases and 1558 controls of the association between CYP1A1 rs1048943 and rs4646903 polymorphisms and laryngeal cancer risk. For CYP1A1 rs1048943 of the homozygote G/G and G allele carriers (A/G + G/G) versus A/A, the pooled ORs were 1.77 (95% CI = 1.28-2.81, P = 0.007 for heterogeneity) and 1.86 (95% CI = 1.45-2.40, P = 0.000 for heterogeneity). For CYP1A1 rs4646903 of the homozygote G/G and G allele carriers (A/G + G/G) versus A/A, the pooled ORs were 1.53 (95% CI = 1.31-2.21, P = 0.012 for heterogeneity) and 1.33(95% CI = 1.04-1.71, P = 0.029 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians for both the G allele carriers and homozygote G/G. However, no significant associations were found in Caucasian population all genetic models. These results from the meta-analysis suggest that CYP1A1 rs1048943 and rs4646903 polymorphisms contribute to risk of laryngeal cancer among Asian populations.

Akhtar S, Mahjabeen I, Akram Z, Kayani MA
CYP1A1 and GSTP1 gene variations in breast cancer: a systematic review and case-control study.
Fam Cancer. 2016; 15(2):201-14 [PubMed] Related Publications
In first part of this study, a systematic review was designed to explore the involvement of CYP1A1 and GSTP1 genes in breast cancerogenesis. Based on systematic review, we designed a study to screen CYP1A1 and GSTP1 genes for mutation and their possible association with breast carcinogenesis. A total of 400 individuals were collected and analyzed by PCR-SSCP. After sequence analysis of coding region of CYP1A1 we identified eleven mutations in different exons of respective gene. Among these eleven mutations, ~3 folds increased breast cancer risk was found associated with Asp82Glu mutation (OR 2.99; 95% CI 1.26-7.09), with Ser83Thr mutation (OR 2.99; 95% CI 1.26-7.09) and with Glu86Ala mutation (OR 3.18; 95% CI 1.27-7.93) in cancer patients compared to controls. Furthermore, ~4 folds increase in breast cancer risk was found associated with Asp347Glu, Phe398Tyr and 5178delT mutations (OR 3.92; 95% CI 1.35-11.3) in patients compared to controls. The sequence analysis of GSTP1 resulted in identification of total five mutations. Among these five mutations, ~3 folds increase in breast cancer risk was observed associated with 1860G>A mutation, with 1861-1876delCAGCCCTCTGGAGTGG mutation (OR 2.70; 95% CI 1.10-6.62) and with 1861C>A mutation (OR 2.97; 95% CI 1.01-8.45) in cancer patients compared to controls. Furthermore, ~5 folds increase in breast cancer risk was associated with 1883G>T mutation (OR 4.75; 95% CI 1.46-15.3) and ~6 folds increase in breast cancer risk was found associated with Iso105Val mutation (OR 6.43; 95% CI 1.41-29.3) in cancer patients compared to controls. Our finding, based on systematic review and experimental data suggest that the polymorphic CYP1A1 and GSTP1 genes may contribute to risk of developing breast cancer.

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