CYP1B1 Leu432Val Research Articles

Pathological characteristics, survival, and risk of breast cancer associated with estrogen and xenobiotic metabolism polymorphisms in Mexican women with breast cancer.

We included 150 controls and 150 cases matched by age. To analyze the selected polymorphisms, TaqMan assays and high-resolution melting (HRM) analysis were used. The polymorphisms of the genes ERα, CYP1A1, CYP1B1, COMT, MGMT, and XRCC1 were positively associated with the BC risk. We found negative associations between CYP1B1G/G genotype and tumor size, and status of lymph node, estrogen receptor, triple negative, and survival. The polymorphisms included in this study are associated not only with the risk of BC, but also with some clinicopathological characteristics for poor prognosis of patients with breast cancer, highlighting the important role of CYP1B1 Leu432Val polymorphism.

Association of cytochrome P450 1B1 gene polymorphisms and environmental biomarkers with hypertension in Slovak midlife women.

This study investigated the association of the Leu432Val and Asn453Ser CYP1B1 polymorphisms and selected environmental biomarkers with hypertension (HT) in Slovak midlife women. We studied 575 women. Divided according to their blood pressure status: 255 with HT and 320 without HT. All data was obtained by using standard anthropometric, genetic methods and analyzed by regression models to adjust for HT risk factors such as age, obesity, smoking, and level of education. Our findings revealed that CYP1B1 Leu432Val polymorphism was associated with HT, whereas no association was found between Asn453Ser polymorphism and HT. Women with at least one Val allele had significantly higher odds of HT compared to women with the Leu/Leu genotype in the total sample (Exp(B) = 1.82, CI 1.16-2.84, P = 0.009). After dividing women by menopausal status and the presence of HT environmental risk factor, the association between CYP1B1 polymorphism and HT was observed in pre/perimenopausal women (Exp(B), 2.36; 95% CI 1.13-4.92; P = 0.02), smokers (Exp(B), 3.40; 95% CI 1.48-7.82; P = 0.004), abdominal obesity (Exp(B), 2.41; 95% CI 1.23-4.75; P = 0.01) and in women with only basic education (Exp(B), 4.20, 95% CI 1.12-15.71; P = 0.03). However, general linear models did not reveal a statistically significant interactions between CYP1B1, menopausal status, and HT risk factors and their common association with HT (P > 0.05). In this pilot study, we have provided novel data that supports the significant association of CYP1B1 Leu432Val gene polymorphism with HT in Slovak midlife women.

Polymorphism in xenobiotic and estrogen metabolizing genes, exposure to perfluorinated compounds and subsequent breast cancer risk: A nested case-control study in the Danish National Birth Cohort

In the present case-cohort study based on prospective data from Danish women, we aimed to estimate the main effect of polymorphisms in genes known to be involved in the steroid hormone metabolic pathway and xenobiotic metabolism on the risk of developing breast cancer. We also studied a possible effect measure modification between genotypes and levels of serum perfluoroalkylated substances (PFASs) on the risk to breast cancer. We have previously reported a weak association between serum PFASs levels and the risk of breast cancer for this study population of Danish pregnant nulliparous women as well as in a smaller case-control study of Greenlandic women.The study population consisted of 178 breast cancer cases and 233 controls (tabnulliparous and frequency matched on age) nested within the Danish National Birth Cohort (DNBC), which was established in 1996-2002. Blood samples were drawn at the time of enrollment (6-14 week of gestation). Serum levels of 10 perfluorocarboxylated acids (PFCAs), 5 perfluorosulfonated acids (PFSAs) and 1 sulfonamide (perflurooctane-sulfonamide, PFOSA) were measured. Genotyping was conducted for CYP1A1 (Ile462Val; rs1048943), CYP1B1 (Leu432Val; rs1056836), COMT (Val158Met; rs4680), CYP17A1 (A1→ A2; rs743572); CYP19A1 (C→T; rs10046) by the TaqMan allelic discrimination method.In overall, no significant associations were found between the investigated polymorphisms and the risk of breast cancer in this study among Danish women. The previously found association between PFOSA and risk of breast cancer did vary between different genotypes, with significantly increased risk confined to homozygous carriers of the following alleles: COMT (Met), CYP17 (A1) and CYP19 (C).Conclusion:Our results indicate that polymorphisms in COMT, CYP17 and CYP19 which are involved in estrogen biosynthesis and metabolism can modulate the potential effects of PFOSA exposure on the development of breast cancer.

Influence of the CYP1B1 gene polymorphisms and uterine leiomyoma risk in Iranian women

Uterine leiomyoma (UL) is the most common gynecological benign tumor with unknown etiology and pathogenesis. This case- control study was performed to investigate the association between CYP1B1gene polymorphisms with uterine leiomyoma in Iranian women. Polymorphisms CYP1B1 Arg48Gly, Ala119Ser, Leu432Val and Asp449Asp were genotyped by using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method in 300 premenopausal women with diagnosed UL (cases) and 200 healthy normal (controls). A significant difference was found for the C allele frequencies of the Leu432Val C>G polymorphism between the two groups (OR = 0.71, P = 0.04, 95 % CI = 0.48 – 1.03). However, no significant difference was found for the CYP1B1 Arg48Gly, Ala119Ser and Asp449Asp polymorphisms between the two groups (p>0.05). Our findings indicated that CYP1B1 Leu432Val CC genotype may be involved in susceptibility to UL in Iranian women.

Association between the CYP1B1 polymorphisms and risk of cancer: a meta-analysis.

The previous, published data on the association between CYP1B1 polymorphisms and cancer risk remained controversial. To derive a more precise estimation of the association between the CYP1B1 polymorphisms and cancer risk, we performed a meta-analysis to investigate the association between cancer susceptibility and CYP1B1 Leu432Val, Asn453Ser, Arg48Gly, and Ala119Ser polymorphisms. For Asn453Ser and Arg48Gly polymorphisms, significantly decreased endometrial cancer was observed among Caucasians. For Ala119Ser polymorphism, we found that individuals with the minor variant genotypes had a high risk of prostate cancer. For Leu432Val polymorphism, we found that individuals with the minor variant genotypes had a higher risk of endometrial cancer and lung cancer and had a lower risk of ovarian cancer. In summary, this meta-analysis suggests that Leu432Val polymorphism is associated with ovarian cancer, lung cancer, and endometrial cancer risk; Asn453Ser and Arg48Gly polymorphisms are associated with endometrial cancer risk among Caucasians, Ala119Ser polymorphism is associated with prostate cancer risk, and Ala119Ser polymorphism is associated with breast cancer risk in Caucasians. In addition, our work also points out the importance of new studies for Ala119Ser polymorphism in endometrial cancer, because high heterogeneity was observed (I (2) > 75 %).

Association between CYP1A2 and CYP1B1 polymorphisms and colorectal cancer risk: a meta-analysis.

BackgroundThe previous published data on the association between CYP1A2*F (rs762551), CYP1B1 Leu432Val (rs1056836), Asn453Ser (rs180040), and Arg48Gly (rs10012) polymorphisms and colorectal cancer risk remained controversial.Methodology/Principal FindingsThe purpose of this study is to evaluate the role of CYP1A2*F, CYP1B1 Leu432Val, Asn453Ser, and Arg48Gly genotypes in colorectal cancer susceptibility. We performed a meta-analysis on all the eligible studies that provided 5,817 cases and 6,544 controls for CYP1A2*F (from 13 studies), 9219 cases and 10406 controls for CYP1B1 Leu432Val (from 12 studies), 6840 cases and 7761 controls for CYP1B1 Asn453Ser (from 8 studies), and 4302 cases and 4791 controls for CYP1B1Arg48Gly (from 6 studies). Overall, no significant association was found between CYP1A2*F, CYP1B1 Leu432Val, Asn453Ser, and Arg48Gly and colorectal cancer risk when all the eligible studies were pooled into the meta-analysis. And in the subgroup by ethnicity and source of controls, no evidence of significant association was observed in any subgroup analysis.Conclusions/SignificanceIn summary, this meta-analysis indicates that CYP1A2*F, CYP1B1 Leu432Val, Asn453Ser, and Arg48Gly polymorphisms do not support an association with colorectal cancer, and further studies are needed to investigate the association. In addition, our work also points out the importance of new studies for CYP1A2*F polymorphism in Asians, because high heterogeneity was found (dominant model: I 2 = 81.3%; heterozygote model: I 2 = 79.0).

Polymorphisms in Phase I and Phase II genes and breast cancer risk and relations to persistent organic pollutant exposure: a case–control study in Inuit women

BackgroundWe have previously reported that chemicals belonging to the persistent organic pollutants (POPs) such as perfluorinated compounds (PFAS) and polychlorinated biphenyls (PCBs) are risk factors in Breast Cancer (BC) development in Greenlandic Inuit women. The present case–control study aimed to investigate the main effect of polymorphisms in genes involved in xenobiotic metabolism and estrogen biosynthesis, CYP1A1, CYP1B1, COMT and CYP17, CYP19 and the BRCA1 founder mutation in relation to BC risk and to explore possible interactions between the gene polymorphisms and serum POP levels on BC risk in Greenlandic Inuit women.MethodsThe study population consisted of 31 BC cases and 115 matched controls, with information on serum levels of POPs. Genotyping was conducted for CYP1A1 (Ile462Val; rs1048943), CYP1B1 (Leu432Val; rs1056836), COMT (Val158Met; rs4680), CYP17A1 (A1> A2; rs743572); CYP19A1 (C> T; rs10046) and CYP19A1 ((TTTA)n repeats) polymorphisms and BRCA1 founder mutation using TaqMan allelic discrimination method and polymerase chain reaction based restriction fragment length polymorphism. The χ2 –test was used to compare categorical variables between cases and controls and the odds ratios were estimated by unconditional logistic regression models.ResultsWe found an independent association of CYP1A1 (Val) and CYP17 (A1) with BC risk.Furthermore, an increased BC risk was observed for women with high serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and carriers of at least: one CYP1A1 variant Val allele; one variant COMT Met allele; or the common CYP17 A1 allele. No combined effects were seen between PFAS exposure and CYP1B1 and CYP19 polymorphisms. The risk of BC was not found significantly associated with exposure to PCBs and OCPs, regardless of genotype for all investigated SNPs. The frequency of the Greenlandic founder mutation in BRCA1 was as expected higher in cases than in controls.ConclusionsThe BRCA1 founder mutation and polymorphisms in CYP1A1 (Val) and CYP17 (A1) can increase the BC risk among Inuit women and the risk increases with higher serum levels of PFOS and PFOA. Serum PFAS levels were a consistent risk factor of BC, but inter-individual polymorphic differences might cause variations in sensitivity to the PFAS/POP exposure.

Quantitative assessment of the influence of CYP1B1 polymorphisms and head and neck squamous cell carcinoma risk

The associations between CYP1B1 polymorphisms and head and neck squamous cell carcinoma (HNSCC) risk have been conflicting. We therefore performed a meta-analysis to derive a more precise relationship. Six published case-control studies were collected; odds ratios (ORs) with 95% confidence interval (CI) were used to assess the association between CYP1B1 Leu432Val, Asn453Ser polymorphisms, and HNSCC risk. The Sensitivity analysis and publication bias also were performed to guarantee the statistical power. Overall, the pooled OR with 95% CIs indicated that CYP1B1 Leu432Val polymorphism was significantly related with HNSCC risk (for Val vs. Leu: OR = 1.13, 95% CI = 1.03-1.25, P = 0.014, P(heterogeneity) = 0.141; for Val/Val vs. Leu/Leu: OR = 1.30, 95% CI = 1.06-1.60, P = 0.013, P heterogeneity = 0.253; for Val/Val vs. Leu/Leu + Leu/Val: OR = 1.23, 95% CI = 1.05-1.46, P = 0.013, P(heterogeneity) = 0.456). The similar results were also been found in succeeding analysis of HWE and stratified analysis of Caucasian population. Furthermore, no significant association between CYP1B1 Asn453Ser polymorphism and HNSCC risk was found in this meta-analysis. In conclusion, our meta-analysis demonstrates that CYP1B1 Leu432Val polymorphism may be a risk factor for developing HNSCC.

Role of single nucleotide polymorphisms in estrogen‐metabolizing enzymes and susceptibility to uterine leiomyoma in Han Chinese: A case–control study

To explore the relationship between estrogen metabolism enzyme gene polymorphism and susceptibility to uterine fibroids, and to seek the screening molecular markers for genetic traits in uterine fibroid populations. A total of 300 female Han Chinese patients and 300 healthy female Han Chinese volunteers in Nanjing (age range, 30-50 years) were recruited from Zhongda Hospital, Southeast University from February 2011 to March 2012. The single nucleotide polymorphisms (SNP) of estrogen-metabolizing enzyme genes from the two groups of women were examined by polymerase chain reaction denaturing high-performance liquid chromatography, which were four COMT gene loci including rs3087869, rs165774, rs165599 and rs4680, three CYP1A1 gene loci including rs1048943, rs4646421 and rs4646422, and three CYP1B1 gene loci including rs1056827, rs1056836 and rs1056837. Genotype frequencies among cases and controls were calculated and analyzed by binary logistic regression. Regression analysis of SNP showed that COMT IVS1+2329C>T (odds ratio [OR], 2.872; 95% CI, 1.690-4.882) and Val158Met (OR, 2.593; 95% CI, 1.546-4.350), CYP1A1 Ile462Val (OR, 2.383; 95% CI, 1.418-4.005) and Gly45Asp (OR, 2.489; 95% CI, 1.49-4.159), and CYP1B1 Ala119Ser (OR, 3.361; 95% CI, 2.035-5.552) and Leu432Val (OR, 0.164; 95% CI, 0.061-0.441) influenced uterine fibroids significantly (P < 0.05). Allele and genotype frequencies among cases and control were calculated and examined to match the Hardy-Weinberg equilibrium with the χ²-test. The genetic polymorphisms of IVS1+2329C>T and Val158Met loci in COMT, Ile462Val and Gly45Asp loci in CYP1A1 and Ala119Ser loci in CYP1B1 were risk factors for uterine leiomyoma development, and Leu432Val locus in CYB1B1 may be a protective factor. The results provide a theoretical basis for genetic screening and early intervention for uterine leiomyoma-susceptible populations.

ATL: A Meta-analysis

Disordered metabolism of estrogen is believed to play a significant role in endometrial carcinogenesis. Recently, a number of studies have been conducted to identify the role of estrogen-related gene polymorphism in endometrial cancer risk, generating conflicting conclusions. This meta-analysis aimed to assess the association between genetic polymorphisms involving estrogen metabolic enzymes and endometrial cancer risk. A systematic search of 6 databases was conducted. Fourteen studies on the association of COMT (catechol-O-methyltransferase) Val158Met, CYP1B1 Leu432Val, and CYP1B1 Asn453Ser polymorphisms with endometrial cancer risk were identified, enrolling a total of 4283 cancer cases and 7094 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the relationship. In CYP1B1 Leu432Val(rs1056836) analysis, the heterozygous genotype (CG) demonstrated an increased risk for endometrial cancer (Val/Leu vs. Leu/Leu: pooled OR, 1.11; 95% CI, 1.01-1.23; P = 0.039; I = 10.5%; (Val/Val +Val/Leu) vs. Leu/Leu: pooled OR, 1.19; 95% CI, 1.03-1.38; P = 0.017; I = 54.7%). As for CYP1B1 Asn453Ser(rs1800440) polymorphism, a decreased risk was observed in G allele compared with A allele (Ser vs. Asn: pooled OR, 0.82; 95% CI, 0.72-0.94; P = 0.005; I = 0.0%), and heterozygous genotype also showed a decreased risk compared with normal genotype (Ser/Asn vs. Asn/Asn: pooled OR, 0.81; 95% CI, 0.69-0.95; P = 0.011; I = 0.0%). As for COMT Val158Met (rs4680) polymorphism, the heterogeneous genotype showed a decreased risk for endometrial cancer compared with the common homogenous genotype in a fixed-effect model in Asian population (Met/Val vs. Val/Val: pooled OR, 0.83; 95% CI, 0.70-0.98; P = 0.033; I = 29.2%), whereas no positive results are found in other subgroups or models. COMT Val158Met was seen to show a decreased risk for endometrial cancer in Asian population. CYP1B1 Leu432Val and Asn453Ser polymorphisms demonstrated an increased and decreased risk for endometrial cancer, respectively. Further large and comprehensive studies in various populations with more detailed individual data are needed to confirm our findings.

Genetic polymorphisms in CYP1A1, CYP1B1 and COMT genes in Greenlandic Inuit and Europeans

BackgroundThe Indigenous Arctic population is of Asian descent, and their genetic background is different from the Caucasian populations. Relatively little is known about the specific genetic polymorphisms in genes involved in the activation and detoxification mechanisms of environmental contaminants in Inuit and its relation to health risk. The Greenlandic Inuit are highly exposed to legacy persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), and an elucidation of gene–environment interactions in relation to health risks is needed.ObjectivesThe aim of this study was to determine and compare the genotype and allele frequencies of the cytochrome P450 CYP1A1 Ile462Val (rs1048943), CYP1B1 Leu432Val (rs1056836) and catechol-O-methyltransferase COMT Val158Met (rs4680) in Greenlandic Inuit (n=254) and Europeans (n=262) and explore the possible relation between the genotypes and serum levels of POPs.ResultsThe genotype and allele frequency distributions of the three genetic polymorphisms differed significantly between the Inuit and Europeans. For Inuit, the genotype distribution was more similar to those reported for Asian populations. We observed a significant difference in serum polychlorinated biphenyl (CB-153) and the pesticide 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p′-DDE) levels between Inuit and Europeans, and for Inuit also associations between the POP levels and genotypes for CYP1A1, CYP1B1 and COMT.ConclusionOur data provide new information on gene polymorphisms in Greenlandic Inuit that might support evaluation of susceptibility to environmental contaminants and warrant further studies.

Menopausal complaints in Slovak midlife women and the impact of CYP1B1 polymorphism on their incidence

A wide variety of symptoms have been attributed to menopause, negatively influencing women's physical and psychological health. In addition to lifestyle parameters and personal history, genetic factors are considered to be the main source of this variation. This study aims to investigate the incidence of menopausal symptoms among midlife women according to their menopausal status, and to evaluate the contribution to their manifestation from CYP1B1 Leu432Val polymorphism as a predisposing factor for menopausal symptoms. The studied cohort consisted of 299 women ranging from 39 to 59 years of age. Women were recruited from the western and middle parts of Slovakia, and all participants completed a menopause-specific questionnaire and provided blood or saliva samples for genotyping. Our results indicated that all women are at risk of typical menopausal symptoms, but there is a higher number of postmenopausal women affected than premenopausal ones. Regression analysis showed that the CYP1B1 Leu/Leu genotype can increase the experience of bloated stomach and facial hair increase in all the sampled women, while the Leu/Leu genotype may increase experience of palpitations and involuntary urination in the premenopausal women. The Leu/Leu genotype may increase the experience of nausea, bloated stomach, and vaginal dryness in peri- and postmenopausal women. We determined that women with the Leu/Leu, or Leu/Val genotypes were approximately five times more likely to suffer from vaginal dryness than the Val/Val women (OR = 4.948; 95% CI, 1.259-19.447). We therefore suggest that CYP1B1 Leu432Val polymorphism could be involved in individual susceptibility to menopausal symptoms in Slovak midlife women.

Polymorphisms in carcinogen metabolism enzymes, fish intake, and risk of prostate cancer.

Cooking fish at high temperature can produce potent carcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons. The effects of these carcinogens may undergo modification by the enzymes responsible for their detoxification and/or activation. In this study, we investigated genetic polymorphisms in nine carcinogen metabolism enzymes and their modifying effects on the association between white or dark fish consumption and prostate cancer (PCA) risk. We genotyped 497 localized and 936 advanced PCA cases and 760 controls from the California Collaborative Case-Control Study of Prostate Cancer. Three polymorphisms, EPHX1 Tyr113His, CYP1B1 Leu432Val and GSTT1 null/present, were associated with localized PCA risk. The PTGS2 765 G/C polymorphism modified the association between white fish consumption and advanced PCA risk (interaction P 5 0.002), with high white fish consumption being positively associated with risk only among carriers of the C allele. This effect modification by PTGS2 genotype was stronger when restricted to consumption of well-done white fish (interaction P 5 0.021). These findings support the hypotheses that changes in white fish brought upon by high-temperature cooking methods, such as carcinogen accumulation and/or fatty acid composition changes, may contribute to prostate carcinogenesis. However, the gene-diet interactions should be interpreted with caution given the limited sample size. Thus, our findings require further validation with additional studies.

Carcinogen metabolism genes, red meat and poultry intake, and colorectal cancer risk

Diets high in red meat are established risk factors for colorectal cancer (CRC). Carcinogenic compounds generated during meat cooking have been implicated as causal agents. We conducted a family-based case-control study to investigate the association between polymorphisms in carcinogen metabolism genes (CYP1A2 -154A>C, CYP1B1 Leu432Val, CYP2E1 -1054C>T, GSTP1 Ile105Val, PTGS2 5UTR -765, EPHX1 Tyr113His, NAT2 Ile114Thr, NAT2 Arg197Gln and NAT2 Gly286Glu) and CRC risk. We tested for gene-environment interactions using case-only analyses (N = 577) and compared statistically significant results to those obtained using case-unaffected sibling comparisons (N = 307 sibships). Our results suggested that CYP1A2 -154A>C might modify the association between intake of red meat cooked using high temperature methods and well done on the inside and CRC risk (case-only interaction OR = 1.53; 95% CI = 1.19-1.97; p = 0.0008) and the association between intake of red meat heavily browned on the outside and rectal cancer risk (case-only interaction OR = 0.65; 95% CI = 0.48-0.86; p = 0.003). We also found that GSTP1 Ile105Val might modify the association between intake of poultry cooked with high temperature methods and CRC risk (p = 0.0035), a finding that was stronger among rectal cancer cases. Our results support a role for heterocyclic amines that form in red meat as a potential explanation for the observed association between diets high in red meat and CRC. Our findings also suggest a possible role for diets high in poultry cooked at high temperatures in CRC risk.

Cyp1B1 mRNA expression in correlation to cotinine levels with respect to the Cyp1B1 L432V gene polymorphism

Cytochrome P450 1B1 (CYP1B1) is involved in the activation of a broad spectrum of procarcinogens. An association of the Cyp1B1 Leu432Val polymorphism with cancer as well as an impact on the enzyme activity has been described. To study gene-environmental interactions we investigated the quantitative Cyp1B1 mRNA expression in smokers (N = 102) and non-smokers (N = 192) with regards to the Cyp1B1 L432V gene polymorphism. Tobacco smoke exposure was assessed by serum cotinine levels. Genotypes were analysed by melting curve analysis and quantification of Cyp1B1 mRNA by real-time PCR. In comparing Cyp1B1 expression, significant differences between the two homozygote genotypes *1/*1 and *3/*3 (0.105 ± 0.019; n = 26 vs. 0.051 ± 0.017; n = 14; P = 0.039) and between the heterozygote genotype *1/*3 and *3/*3 (0.121 ± 0.029; n = 55 vs. 0.051 ± 0.017; n = 14; P = 0.039) of smokers were revealed. According to the serum cotinine levels, three subgroups (low; medium; high) were build. The group "high" (0.248 ± 0.089; n = 32) showed proportionally high Cyp1B1 mRNA expression compared to "medium" (0.101 ± 0.024; n = 33), "low" (0.086 ± 0.015; n = 32) and non-smokers (0.084 ± 0.007; n = 176). This result was reflected in the homozygote *1/*1 and the heterozygote *1/*3 genotypes. In contrast the homozygote *3/*3 genotype was missing the high Cyp1B1 mRNA expression in the cotinine subgroup "high". Our results suggest that genotypes carrying the C-allele (*1/*1 and *1/*3) at Cyp1B1 Leu432Val polymorphism show a higher response to environmental factors, such as tobacco smoke than homozygote *3/*3 genotypes.

Is genetic polymorphism of ER-α, CYP1A1, and CYP1B1 a risk factor for uterine leiomyoma?

Uterine leiomyoma is the most common benign smooth muscle tumor. This study was carried out to evaluate the association of ER-α, CYP1A1, and CYP1B1 polymorphisms with uterine leiomyoma in Egyptian women. The study population consisted of 160 patients with uterine leiomyoma and 100 healthy women as control. The genetic polymorphisms for ER-α MSP1 exon 1, CYP1B1 Leu432Val, and CYP1A1 Ile462Val were analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods. There were no statistically significant differences in the overall associations between the ER-α exon I CT genotypes and uterine leiomyoma (P = 0.47). However, an elevated risk of uterine leiomyoma was observed among women with the CYP1A1 Ile462Val AG genotype (P = 0.07) and CYP1B1 Leu 432Val C/C genotype (P = 0.08). We concluded that the carriage of CYP1A1 Ile462Val AG and CYP1B1 Leu 432Val CC genotypes predict the susceptibility to leiomyoma in Egyptian women and they are likely to contribute in the pathogenesis of leiomyoma.

Frequencies of CYP1B1 and CYP2F1 polymorphic variants in three ethnic groups of Bashkortostan and in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a multifactorial respiratory disorder. Members of the cytochrome P450 family catalyze oxidative metabolism of exogenous chemicals and activate their substrates into reactive intermediates that may initiate lung injury. The frequencies of CYP1B1 and CYP2F1 polymorphic markers were determined in healthy people from Bashkortostan and tested for association with COPD. Using PCR-RFLP, the polymorphic markers Leu432Val (CYP1B1) and c.14-15insC (CYP2F1) were studied in healthy Russians (N = 191), Tatars (N = 198), and Bashkirs (N = 78) and in Russian (N = 169) and Tatar (N = 137) COPD patients. The CYP2F1 genotype frequency distribution proved to differ between the three ethnic groups (χ 2 = 21.29, d.f. = 4, P = 0.0001), Tatars having a higher frequency of the c.14-15insC/c.14-15insC genotype (6.38%). The highest frequency (39.74%) of the heterozygous genotype was observed in Bashkirs. The frequency of the insertion-free CYP2F1 variant in Tatars with extremely severe COPD and onset after 55 years of age was significantly higher (87.5%) than in patients of the same age group with moderate or severe COPD (87.50% vs. 75.53%, χ 2 = 3.964, d.f. = 1, P = 0.046; OR = 2.268). The allele and genotype frequency distributions of the CYP1B1 Leu432Val polymorphism were similar in the Russian, Tatar, and Bashkir ethnic groups. Leu432Val of CYP1B1 was not associated with COPD.

Genetic polymorphisms in estrogen metabolism and breast cancer risk in case–control studies in Japanese, Japanese Brazilians and non-Japanese Brazilians

Although many studies have examined associations between single nucleotide polymorphisms (SNPs) in the CYP1A1, CYP1A2 and CYP1B1 genes and breast cancer risk, no study has examined functional SNPs in the CYP3A5 gene and only a small number of studies have been investigated in Japanese populations. To examine the association between six SNPs, CYP1A1(*)2A, CYP1A1(*)2C, CYP1A2(*)1F, CYP1B1 Arg(48)Gly, CYP1B1 Leu(432)Val and CYP3A5*3 and breast cancer risk, therefore, we conducted hospital-based case-control studies in Nagano, Japan and São Paulo, Brazil including 873 pairs (403 Japanese (JJ), 81 Japanese Brazilians (JB) and 389 non-Japanese Brazilians (NJB)). Although we found no significant association in the three populations combined, subgroup analyses revealed statistically significant associations of CYP1A2*1F in NJB, and CYP1B1 Leu(432)Val and CYP3A5*3 in JJ with breast cancer risk. Compared to women with the AA genotype in CYP1A2*1F, the odds ratio (OR) (95% confidence interval (CI)) for NJB with the CC genotype was 0.54 (0.32-0.90); that for JJ with Leu/Val+Val/Val versus Leu/Leu genotype in CYP1B1 Leu(432)Val was 0.68 (0.48-0.97); and that for JJ with (*)3/(*)1+(*)1/(*)1 versus (*)3/(*)3 genotype in CYP3A5*3 was 1.49 (1.10-2.04). Our findings provide further evidence that genetic polymorphisms related to estrogen metabolism may play a role in the development of breast cancer.

Head and Neck Squamous-Cell Cancer and its Association with Polymorphic Enzymes of Xenobiotic Metabolism and Repair

Tobacco smoking, alcohol drinking, and occupational exposures to polycyclic aromatic hydrocarbons are the major proven risk factors for human head and neck squamous-cell cancer (HNSCC). Major research focus on gene–environment interactions concerning HNSCC has been on genes encoding enzymes of metabolism for tobacco smoke constituents and repair enzymes. To investigate the role of genetically determined individual predispositions in enzymes of xenobiotic metabolism and in repair enzymes under the exogenous risk factor tobacco smoke in the carcinogenesis of HNSCC, we conducted a case-control study on 312 cases and 300 noncancer controls. We focused on the impact of 22 sequence variations in CYP1A1, CYP1B1, CYP2E1, ERCC2/XPD, GSTM1, GSTP1, GSTT1, NAT2, NQO1, and XRCC1. To assess relevant main and interactive effects of polymorphic genes on the susceptibility to HNSCC we used statistical models such as logic regression and a Bayesian version of logic regression. In subgroup analysis of nonsmokers, main effects in ERCC2 (Lys751Gln) C/C genotype and combined ERCC2 (Arg156Arg) C/A and A/A genotypes were predominant. When stratifying for smokers, the data revealed main effects on combined CYP1B1 (Leu432Val) C/G and G/G genotypes, followed by CYP1B1 (Leu432Val) G/G genotype and CYP2E1 (–70G>T) G/T genotype. When fitting logistic regression models including relevant main effects and interactions in smokers, we found relevant associations of CYP1B1 (Leu432Val) C/G genotype and CYP2E1 (–70G>T) G/T genotype (OR, 10.84; 95% CI, 1.64–71.53) as well as CYP1B1 (Leu432Val) G/G genotype and GSTM1 null/null genotype (OR, 11.79; 95% CI, 2.18–63.77) with HNSCC. The findings underline the relevance of genotypes of polymorphic CYP1B1 combined with exposures to tobacco smoke.

CYP1B1, CYP1A1, MPO, and GSTP1 polymorphisms and lung cancer risk in never-smoking Korean women

Polymorphisms in metabolic genes encoding phase I and phase II enzymes are thought to modulate the risk of lung cancer via changes in enzymatic activity. Recently, the effect of these metabolic enzymes and their interaction with environmental factors has been studied in both smokers and also never-smokers, since never-smokers are a good model in which to study genetic susceptibility at low-dose carcinogen exposure. Here, we investigated the association of CYP1A1 Ile462Val, CYP1B1 Leu432Val, GSTP1 Ile105Val, MPO G-463A polymorphisms and lung cancer risk in never-smoking Korean women. In this case-control study of 213 lung cancer patients and 213 age-matched healthy controls, we found that carrying one variant allele of the CYP1A1 Ile462Val polymorphism was associated with a significantly decreased risk of lung adenocarcinoma (adjusted odds ratio (OR)=0.63; 95% confidence interval (CI), 0.41-0.99). Furthermore, the combination of risk genotypes of CYP1B1 Leu432Val with CYP1A1 Ile462Val was associated with the risk of lung adenocarcinoma (adjusted OR=2.16; 95% CI, 1.02-4.57) as well as overall lung cancer (adjusted OR=2.23; 95% CI 1.01-4.89). The polymorphisms of GSTP1 Ile105Val and MPO G-463A showed no significant association with lung cancer. Theses results suggest that the CYP1A1 Ile462Val polymorphism is associated with a reduced risk of lung adenocarcinoma in never-smoking Korean women, whereas specific combinations of variant genotypes for metabolic enzymes increase lung cancer risk considerably.