Germ line polymorphisms in cytochrome-P450 1A1 (C4887 CYP1A1) and methylenetetrahydrofolate reductase (MTHFR) genes and endometrial cancer susceptibility

We describe here a case-control study to identify associations between polymorphisms at the methylenetetrahydrofolate reductase (MTHFR) and cytochrome P-450 1A1 (CYP1A1) genes and susceptibility to endometrial cancer. Accordingly, genotype frequencies in 80 endometrial carcinoma patients were compared with frequencies in 60 controls. DNA analysis suggest a significantly increased endometrial cancer risk with an alanine to valine substitution at nucleotide 677 of MTHFR gene with an odds ratio of 2.8 (95% confidence interval: 1.36-6.14, P = 0.002). Moreover, the tumors from patients with the valine allele were more undifferentiated (P = 0.03). On the other hand, a recently described mutation in exon 7 of CYP1A1 gene (threonine exchanged to asparagine in codon 461) showed a strong association with endometrial cancer risk with an odds ratio of 6.36 (95% confidence interval: 1.99-26.5, P = 0.0004). Thus, this study suggests that polymorphisms at MTHFR and a novel CYP1A1 variant could influence susceptibility to endometrial cancer, although larger sample sizes would be required to corroborate these findings.      

CYP1A1, SULT1A1, and SULT1E1 polymorphisms are risk factors for endometrial cancer susceptibility

BACKGROUND: In estrogen biosynthetic pathways, many enzymes are important for metabolism, detoxification, and bioavailability. Polymorphisms in these genes may have an effect on the enzymes' function. For example, higher expression and activation of biosynthetic enzymes and lower expression and activation of conjugation enzymes may lead to high toxicity or carcinogenesis. The authors hypothesized that single nucleotide polymorphisms (single nucleotide polymorphisms) of CYP1A1, CYP1A2, CYP1B1, CYP17, SULT1A1, SULT1E1, and SHBG genes may be risk factors for endometrial cancer. METHODS: DNA samples from 150 cases of endometrial cancer and healthy controls (n = 165) were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the genotypic frequency of 13 different polymorphic loci on the CYP1A1 (m1, m2, m3, m4), CYP1A2 1F, CYP1B1 codon432, COMT codon158, CYP17, SULT1A1 (Arg213His, 14A/G, 85C/T in the 3' flanking region), SULT1E1-64G/A promoter region, and SHBG genes. Genotyping was validated by direct DNA sequencing. The authors also investigated the relation between expression of CYP1A1 in endometrial cancer tissues and genotypes of CYP1A1 m1. RESULTS: A decreased frequency of TC + CC genotype of the CYP1A1 m1 (T/C) polymorphism was observed in endometrial cancer patients compared with controls (OR = 0.42; 95% CI, 0.27-0.69). The T-A haplotype of CYP1A1 m1 and m2 was increased in endometrial cancer patients (P = .017). The frequency of CYP1A1 m1 T/C + C/C was higher in a high CYP1A1 expression group (P = .009). The authors also found that individuals carrying the variants of SULT1A1 codon213 and 2 single nucleotide polymorphisms in the 3' flanking region (14A/G and 85C/T) had an increased risk for endometrial cancer. The frequencies of G-A-C and A-G-T haplotypes of these 3 variants were higher in endometrial cancer patients (P < .0001; P = .0002). In addition, the frequency of combined genotypes (SULT1A1 213 GA + AA and CYP1A1 m1 TT) was higher in endometrial cancer patients. (OR, 4.58; 95% CI, 2.35-8.93). CONCLUSIONS: This is the first report on the combined association of CYP1A1 and SULT gene polymorphisms in endometrial cancer that suggests a decreased single nucleotide polymorphism of CYP1A1 and an increased single nucleotide polymorphism for SULT1A1 and SULT1E1 genes may be risk factors for endometrial cancer in Caucasians.     

Cytochrome P450 1A1, cigarette smoking,and risk of endometrial cancer (United States)

Cytochrome P450 1A1 (CYP1A1) is involved in the metabolism of estradiol and the activation of polycyclic aromatic hydrocarbons found in tobacco products. Polymorphic variation in CYP1A1 activity may modify susceptibility to endometrial cancer through the oxidative metabolism of estradiol and the activation of tobacco-smoke constituents. We prospectively evaluated the associations between three common CYP1A1 polymorphisms and endometrial cancer risk, as well as the potential modification of these associations by cigarette smoking, in a case–control study nested within the Nurses’ Health Study. We investigated the MspI restriction-site polymorphism, a C → A transversion at nucleotide 4887 (Thr461Asn) and a A → G transition at nucleotide 4889 (Ile462Val) among 456 women with endometrial cancer and 1,134 matched controls. We used conditional logistic regression to calculate the adjusted odds ratios (OR) and 95% confidence intervals (CI) to quantify the risk of endometrial cancer among subjects who had at least one variant allele compared with that of subjects homozygous for the wild-type allele. We did not observe any statistically significant associations between the MspI, Thr461Asn or Ile462Val polymorphisms and endometrial cancer risk or any significant effect modification by cigarette-smoking status. These data suggest that these three polymorphisms are not important in determining genetic susceptibility to endometrial cancer, although larger sample sizes are needed to confirm these findings.     

CYP17 MspA1Ⅰ基因多态性和月经生育史与子宫内膜癌关系的病例对照研究

目的 研究细胞色素CYP17 MspA1 Ⅰ基因多态性与子宫内膜癌发生的关系。方法采用Taqmam特异性等位基因鉴别方法,对832例子宫内膜癌患者和781例正常对照者的CYP17MspA1 Ⅰ基因多态性进行分析。以非条件Logistic回归模型计算各种基因型发生子宫内膜癌的比数比（OR）及其95％置信区间（CI）。结果 在781例正常对照组中,CYP17 MspA1 Ⅰ位点A1／A1、A1／A2、A2／A2等3种基因型的频率分别为17．8％、49．3％和32．9％。无论绝经与否,CYP17MspA1 Ⅰ基因型与子宫内膜癌的发生均无关,但在携带A2等位基因且未绝经的女性中,怀孕次数多者发生子宫内膜癌的危险降低（OR=0．66,95％ CI 0．44～0．99）。在绝经后女性中,怀孕次数〉2或行经年数≤32年且具有A2等位基因者发生子宫内膜癌的危险降低（OR=0．68,95％CI 0．47～0．99;OR=0．54,95％CI 0．37～0．81）。结论CYP17MspA1 Ⅰ基因多态性单独存在可能与上海市区女性子宫内膜癌的发生无关。     

CYP19 (aromatase) haplotypes and endometrial cancer risk

Endogenous estrogen exposure is an important determinant of endometrial cancer risk. Aromatase, encoded by CYP19, catalyzes the aromatization of androstenedione and testosterone to estrone and estradiol, respectively. Several common genetic polymorphisms in CYP19 have been identified, including a TCT insertion/deletion and a (TTTA)(n) repeat polymorphism in intron IV as well as a 3'UTR C/T polymorphism. We evaluated these 3 polymorphisms plus an additional 9 noncoding polymorphisms as individual genotypes and predicted haplotypes as risk factors for endometrial cancer using a nested case-control study design. Invasive endometrial cancer cases (n = 222) and matched controls (n = 666) were identified among participants in the Nurses' Health Study who had provided a blood sample in 1989-1990 (n = 32,826). We estimated haplotypes from unphased genotype data spanning > 123 kb of CYP19. Six haplotypes constructed from 10 SNPs were estimated with a frequency > or = 5%. The highest prevalence haplotype (33% among cases, 28% among controls) was significantly associated with endometrial cancer risk (p = 0.03). Loci with variant alleles that comprise the risk haplotype were independently associated with endometrial cancer, with relative risk estimates ranging from 1.68 (95% CI 1.13-2.48) to 2.07 (95% CI 1.33-3.23), comparing variant allele carriers to wild-type homozygotes. We observed significant interactions between menopausal status and 2 of the high-risk loci (p = 0.03 and p < 0.01), with > 2-fold increased risk for variant allele carriers who were postmenopausal but no association between genotype and endometrial cancer among premenopausal women. We evaluated associations between CYP19 haplotypes and plasma steroid hormone levels. The haplotype associated with endometrial cancer risk is also significantly associated with the ratios of estrone to androstenedione and estradiol to testosterone, the products and substrates of the enzyme aromatase, encoded by CYP19. Our data suggest that there is a high-frequency CYP19 haplotype related to higher estrogen to androgen ratios and increased risk of endometrial cancer and that this association may primarily pertain to postmenopausal women.     

Cytochrome P450 1A1 (CYP1A1) polymorphism and susceptibility to esophageal cancer: an updated meta-analysis of 27 studies

Cytochrome P450 1A1 (CYP1A1) polymorphisms are known to play a crucial role in the development and metastasis of malignant diseases including esophageal cancer. However, the results of previous studies investigating the association between CYP1A1 polymorphisms and esophageal cancer risk have been inconsistent. This meta-analysis of 27 eligible studies, encompassing 4,215 esophageal cancer cases and 6,339 control subjects, pooled the odds ratios (ORs) with corresponding 95 % confidence intervals (95 % CI) to assess this association. The effects of ethnicity (Caucasian and Asian) and histopathology type (esophageal squamous cell carcinoma and esophageal adenocarcinoma) were considered in subgroup analyses. A significant association was observed between the CYP1A1 Ile/Val gene polymorphism and esophageal cancer in all of the genetic models (Ile/Val vs. Ile/Ile, OR?=?1.41, 95 % CI?=?1.25–1.58; Val/Val vs. Ile/Ile, OR?=?1.94, 95 % CI?=?1.34–2.82; Ile/Val?+?Val/Val vs. Ile/Ile, OR?=?1.49, 95 % CI?=?1.33–1.66). The subgroup analysis based on ethnicity showed that the association between the CYP1A1 Ile/Val polymorphism and esophageal cancer existed in Asian and Caucasian populations. However, no association was observed between the CYP1A1 MspI polymorphism and esophageal cancer in either subgroup or in the overall population. These results suggested that the CYP1A1 Ile/Val polymorphism was associated with an increased risk of esophageal cancer, whereas the CYP1A1 MspI polymorphism may not have increased susceptibility to esophageal cancer. Further studies are required to confirm these findings.     

p53 mutations of lung cancer are not significantly affected by CYP1A1 or GSTM1 polymorphisms

Cytochrome p4501A1 gene (CYP1A1) and glutathione S-transferase mu gene (GSTM1) are involved in the metabolic activation or detoxification of environmental carcinogens including benzo[a]pyrene in tobacco smoke. Individuals with both Val/Val and C type of CYP1A1 (CYP1A1; Val/Val and CYP1A1; C) or homozygous null (-/-) genotype of GSTM1 gene (GSTM1; -/-) show increased susceptibility to lung cancer. The incidence of p53 gene mutations are related to the smoking index of the lung cancer patients. Therefore we determined genotypes of these enzymes and screened p53 gene mutations in 123 non-small cell lung cancer (NSCLC) patients. p53 gene mutations were found in 35% (43/123) of the patients. The incidence of p53 gene mutation CYP1A1; Val/Val (60.0%), CYP1A1; C (50.0%) tended to be higher than those of CYPIAI; Ile/Ile and Ile/Val (40.4%) or CYP1A1; A and B (40.5%). We conclude that the incidence of the p53 mutations does not seem to be significantly affected by only CYP1A1 or GSTM1 polymorphisms in lung cancer patients.     

Polymorphisms in the CYP19A1 (aromatase) gene and endometrial cancer risk in Chinese women.

Aromatase, encoded by the CYP19A1 gene, is a key enzyme in estradiol biosynthesis, which catalyzes the conversion of androstenedione and testosterone to estrone and estradiol, respectively. Given the critical role of estrogen in the development of endometrial cancer risk, we evaluated genetic polymorphisms of the CYP19A1 gene, including rs1065779, rs700519, rs28566535, rs752760, and rs1870050, in association with endometrial cancer in a population-based case-control study conducted in Shanghai, China. Genotypes of 1,040 incident endometrial cancer cases and 1,031 frequency-matched controls were included in the study. We applied a logistic regression model to derive adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). Six common haplotypes with a frequency >or=5% were estimated; the highest frequency haplotype was GCACA (27.8% in cases and 26.2% in controls). We observed an inverse association between CYP19A1 haplotype TCATC and endometrial cancer in our population (OR, 0.76; 95% CI, 0.62-0.92). An inverse association was found between endometrial cancer and single nucleotide polymorphism rs1870050 in the promoter region with ORs of 0.81 (95% CI, 0.68-0.97) and 0.58 (95% CI, 0.42-0.80) for the AC and CC genotypes, respectively. We observed a multiplicative interaction between single nucleotide polymorphism rs700519 and body mass index among postmenopausal women (P = 0.01), with stronger associations between rs700519 genotypes and endometrial cancer risk among heavier (body mass index, >or=25) postmenopausal women. In summary, our data show that polymorphisms in the CYP19A1 gene may contribute to endometrial carcinogenesis.     

Genetic polymorphisms and susceptibility to esophageal cancer among Chinese population (review)

Esophageal cancer, which is prevalent in China and some other parts of the world, is a complex disease likely resulting from polymorphisms of multiple interacting genes and gene-environment interactions. Recent efforts have been made to analyze the associations between risk of this cancer and hereditary sequence variations in genes involved in metabolism, DNA repair and cell cycle control. We summarized here the results of published case-control studies that have examined the effects of common alleles of 15 genes, MTHFR, CYP1A1, CYP2A6, CYP2E1, GSTM1, GSTT1, GSTP1, NAT2, XRCC1, XPD, hOGG1, MGMT, p53, CNDD1 and L-Myc, on risk of esophageal squamous cell carcinoma among Chinese. Statistically significant differences in genotype frequencies found in case-control comparisons were MTHFR C677T and A1298C polymorphisms, the XRCC1 Arg194Trp polymorphisms, the hOGG1 Ser326Cys polymorphism, and the p53 Arg72Pro polymorphism. The overall effects of these genetic polymorphisms were moderate in terms of relative risk, with ORs ranging from 2-10. There was also some evidence that genetic polymorphisms in certain carcinogen-metabolizing enzymes such as CYP2E1, CYP1A1, CYP2A6, GSTM1, and GSTP1 modulate risk of the cancer, although the results require confirmation with larger sample size studies. For polymorphisms in GSTT1, XPD, CCND1, and L-Myc, the risk estimate from the studies was sufficiently precise to exclude an OR >/=1.5.     

Genetic Polymorphisms of the Human Cytochrome P450 1A1 (CYP1A1) and Cervical Cancer Susceptibility among Northeast Thai Women

Background: CYP1A1 is an enzyme in phase I of the cytochrome P450 (CYP) superfamily, and plays a key role in detoxification of carcinogens. Host genetic predisposition in the CYP1A1 may be associated with an increased susceptibility to cervical cancer.The study aimed to evaluate four common polymorphisms of the CYP1A1 and cervical cancer susceptibility among Northeast Thai women. Methods: A case-control study was conducted involving 204 patients with squamous cell cervical cancer (SCCA) and 204 age-matched healthy controls. DNA was extracted from peripheral blood leucocytes. CYP1A1 m1, m3, and m4 genotypes were detected using PCR-RFLP, whereas the CYP1A1 m2 genotype was investigated using real-time PCR. Haplotype analysis was performed using PHASE algorithm version 2.1.1. Results: CYP1A1 m3 was monomorphic. Association between the common CYP1A1 polymorphisms, m1 and m2, and cervical cancer risk was not observed (p>0.05), nor was any association found between the m1–m2–m4 haplotype and cervical cancer risk (p>0.05). Interestingly, the CA genotype of CYP1A1 m4 was observed in 30.88% of the cervical cancer patients but was absent in healthy controls. Conclusion: Our results demonstrated a possible involvement of the CYP1A1 m4 polymorphism but no other common polymorphisms (viz., m1, m2, and m3) in the risk for cervical cancer.This finding may be useful when screening for risk of cervical cancer among Northeast Thai women.     

Impact of AhR,CYP1A1 and GSTM1 Genetic Polymorphisms on TP53 R273G Mutations in Individuals Exposed to Polycyclic Aromatic Hydrocarbons

This study was to undertaken to investigate the impacts of AhR, CYP1A1, GSTM1 genetic polymorphisms onthe R273G mutation in exon 8 of the tumor suppressor p53 gene (TP53) among polycyclic aromatic hydrocarbons(PAHs) exposed to coke-oven workers. One hundred thirteen workers exposed to PAH and 82 control workerswere recruited. We genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and TP53 R273G mutation inblood by PCR methods, and determined the levels of 1-hydroxypyrene as PAH exposure marker in urine usingthe high pressure liquid chromatography assay. We found that the distribution of alcohol users and the urinaryexcretion of 1-OHP in the exposed workers were significantly higher than that of the control workers (p=0.004,p<0.001, respectively). Significant differences were observed in the p53 genotype distributions of smokingsubjects (p=0.01, 95%CI: 1.23-6.01) and PAH exposure (p=0.008, 95%CI: 1.24-4.48), respectively. Further,significant differences were observed in the p53 exon 8 mutations for the genetic polymorphisms of Lys/Argfor AhR (p=0.02, 95%CI: 0.70-15.86), Val/Val for CYP1A1 (p=0.04, 95%CI: 0.98-19.09) and null for GSTM1(p=0.02, 95%CI: 1.19-6.26), respectively. Our findings indicated that polymorphisms of PAH metabolic genes,such as AhR, CYP1A1, GSTM1 polymorphisms may interact with p53 genetic variants and may contribute toPAH related cancers.     

Interaction between CYP19A1 polymorphisms and body mass index in the risk of endometrial cancer in postmenopausal Japanese women

Extra-ovarian sex hormone production plays an important role in endometrial cancer in postmenopausal women. Aromatase, which is encoded by CYP19A1, is a key enzyme in estrogen biosynthesis after menopause. To examine the association between polymorphisms in CYP19A1 and endometrial cancer risk among postmenopausal Japanese women, we conducted a hospital-based case control study in 48 patients with histologically diagnosed incident endometrial cancer and 253 non-cancer control subjects. Information on lifestyle factors was obtained from a self-administered questionnaire. Twenty-five tag SNPs (single nucleotide polymorphisms) of CYP19A1 were examined by TaqMan methods and haplotype blocks were identified by LD analysis. Associations were assessed by an unconditional logistic regression model adjusted for potential confounders. We found no significant association between CYP19A1 genotypes and haplotypes and endometrial cancer risk. However, among women with a BMI (body mass index) >23, significantly positive associations were observed for rs2899473, rs1865803, rs16964220, rs2008691, rs17647707, rs17647719, rs1902586, rs936306, and rs1004982, while negative associations were seen for rs1902585, rs752760 and rs2445768. These showed significant interactions with BMI. Further, of the six haplotype blocks identified, the haplotype CTT of block 1, GATA of block 5 and CA of block 6 showed statistically significant interactions with BMI. These results suggest that CYP19A1 polymorphisms might play an important role in the etiology of endometrial cancer, and that the effect of these polymorphisms might be influenced by BMI.     

CYP1A1, GSTM1, GSTT1 and TP53 Polymorphisms and Risk of Gallbladder Cancer in Bolivians

The Plurinational State of Bolivia (Bolivia) has a high incidence rate of gallbladder cancer (GBC). However, the genetic and environmental risk factors for GBC development are not well understood. We aimed to assess whether or not cytochrome P450 (CYP1A1), glutathione S-transferase mu 1 (GSTM1), theta 1 (GSTT1) and tumor suppressor protein p53 (TP53) genetic polymorphisms modulate GBC susceptibility in Bolivians. This case-control study covered 32 patients with GBC and 86 healthy subjects. GBC was diagnosed on the basis of histological analysis of tissues at the Instituto de Gastroenterologia Boliviano Japones (IGBJ); the healthy subjects were members of the staff at the IGBJ. Distributions of the CYP1A1 rs1048943 and TP53 rs1042522 polymorphisms were assayed using PCR-restriction fragment length polymorphism assay. GSTM1 and GSTT1 deletion polymorphisms were detected by a multiplex PCR assay. The frequency of the GSTM1 null genotype was significantly higher in GBC patients than in the healthy subjects (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.03-5.37; age-adjusted OR, 3.53; 95% CI, 1.29-9.66; age- and sex-adjusted OR, 3.40; 95% CI, 1.24-9.34). No significant differences were observed in the frequencies of CYP1A1, GSTT1, or TP53 polymorphisms between the two groups. The GSTM1 null genotype was associated with increased GBC risk in Bolivians. Additional studies with larger control and case populations are warranted to confirm the association between the GSTM1 deletion polymorphism and GBC risk suggested in the present study.     

Cytochrome P450 1B1 and catechol-O-methyltransferase polymorphisms and endometrial cancer susceptibility

Estrogen production and metabolism play critical roles in the development and pathogenesis of endometrial carcinoma. Cytochrome P450 1B1 (CYP1B1) and catechol-O-methyltransferase (COMT) are two key enzymes in the estrogen metabolism pathway that result in the hydroxylation and conjugation of estradiol, respectively. We evaluated the association between the CYP1B1 Leu432Val and CYP1B1 Asn453Ser polymorphisms and the COMT Val158Met polymorphism and invasive endometrial cancer risk in a case-control study nested within the Nurses' Health Study (n = 222 cases, 666 controls). We also evaluated whether body mass index (BMI), postmenopausal hormone (PMH) use and cigarette smoking modified the associations of the CYP1B1 and COMT genotypes and endometrial cancer risk. Conditional logistic regression was used to calculate the adjusted odds ratios (OR) and 95% confidence intervals (CI) to quantify the risk of endometrial cancer among subjects who had at least one variant allele compared with subjects who were homozygous for the wild-type allele. Carriers of the CYP1B1 Ser allele had a statistically significant decreased risk of endometrial cancer (OR = 0.62; 95% CI, 0.42-0.91); there was no significant association between the CYP1B1 Val allele and endometrial cancer risk (OR = 1.10; 95% CI, 0.75-1.59). Compared with the COMT Val/Val wildtype genotype, the adjusted OR of endometrial cancer for women with the COMT Val/Met or COMT Met/Met genotype was 0.96 (95% CI, 0.65-1.43). We did not observe any effect modification by BMI, PMH use and cigarette smoking for the CYP1B1 and COMT genotypes. Our data suggest, that the CYP1B1 Ser allele may decrease endometrial cancer risk by altering the production of catechol estrogens. However, further studies are warranted to elucidate the role of CYP1B1 in endometrial cancer.     

Genetic polymorphism of cytochrome P450 (CYP) 1A1, CYP1A2, and CYP2E1 genes modulate susceptibility to gastric cancer in patients with Helicobacter pylori infection

Background

Activity of cytochrome P450 (CYP), a polymorphic carcinogen-activating enzyme, is exaggerated following Helicobacter pylori infection. We studied the role of CYP2E1, CYP1A2 (rs762551), and CYP1A1 (rs4646903) polymorphisms in association with H. pylori infection in gastric carcinogenesis.

Methods

Genotyping of CYP2E1 (96-bp insertion), CYP1A2 (164A to C), and CYP1A1 (3801C to T) was carried out in 88, 76, 53, and 170 patients with gastric cancer (GC), functional dyspepsia (FD), peptic ulcer (PU), and healthy controls (HC), respectively. Serum IgG antibody (all subjects), rapid urease test, and histology (GC, FD, and PU patients) were used to test for H. pylori.

Results

CYP2E1 gene polymorphism was more common among patients with GC than HC and PU [48/88 (54.5 %) vs. 67/170 (39.4 %); OR 1.9, 95 % CI 1.1–3.2, p = 0.016) and [PU 18/53 (34 %); OR 2.3 (1–4.7), p = 0.02]. CYP1A2 CC or CT genotypes was lower among patients with GC than HC [50/88 (56.8 %) vs. 120/170 (70.6 %); OR 0.54 (0.31–0.92), p = 0.023]. CYP1A1 polymorphism and CYP1A1–CYP1A2 haplotypes were comparable among different groups. CYP2E1 was also more common in patients with GC than HC and PU in the absence of H. pylori [33/60 (55 %) vs. 19/52 (36.5 %); OR 4 (1.5–11.4), p = 0.007 and PU 7/22 (31.8 %); OR 3.4 (1–11.6), p = 0.05]. CYP1A1 (CT + TT) was more common in patients with GC than PU in presence of H. pylori [17/26 (65.4 %) vs. 11/29 (38 %); OR 3.0 (1.03–9.3), p = 0.045].

Conclusions

The presence of CYP2E1 (96-bp insertion) is associated with increased risk of GC even in absence of H. pylori. CYP1A2 CC or CT is associated with reduced risk of GC.     

CYP1B1 gene polymorphisms have higher risk for endometrial cancer,and positive correlations with estrogen receptor alpha and estrogen receptor beta expressions

The estradiol metabolites by CYP1B1 received particular attention because of their causative role in malignant transformation of endometrium. We hypothesize that polymorphisms of CYP1B1 gene can predict higher incidence of endometrial cancer. To test this hypothesis, the genetic distributions of six different CYP1B1 gene polymorphisms were investigated, by sequence-specific PCR and direct DNA sequencing, in 113 Japanese endometrial cancer patients and 202 healthy controls. We also investigated whether the expression of estrogen receptors (ERalpha and ERbeta), progesterone receptor, and androgen receptor genes are influenced by the CYP1B1 genotypes in endometrial cancer. The results of our study demonstrated that the distributions of CYP1B1 genotypes at codons 119 and 432 were significantly different between endometrial cancer patients and healthy normal controls. The relative risks of 119T/T and 432G/G in endometrial cancer were calculated as 3.32 and 2.49 compared with wild-types. The 119T/T showed significant correlation for positivities of ERalpha and ERbeta. The 432G/G also showed weak correlations for ERalpha positivity. Other loci, intron 1, codon 48, and codon 449 were not different between endometrial cancer patients and healthy normal control. This is the first report that demonstrates that the rare polymorphisms at codons 119 and 432 of CYP1B1 gene have higher risk for endometrial cancer, and positive correlations with ERalpha and ERbeta expressions in endometrial cancer.     

CYP1A1 (Ile462Val), CYP1B1 (Ala119Ser and Val432Leu), GSTM1 (null), and GSTT1 (null) Polymorphisms and Bladder Cancer Risk in a Turkish Population

We aimed to investigate bladder cancer risk with reference to polymorphic variants of cytochrome p450 (CYP)1A1, CYP1B1, glutathione S-transferase (GST) M1, and GSTT1 genes in a case control study. Polymorphismswere examined in 114 bladder cancer patients and 114 age and sex-matched cancer-free subjects. Genotypes weredetermined using allele specific PCR for CYP1A1 and CYP1B1 genes, and by multiplex PCR and melting curveanalysis for GSTM1 and GSTT1 genes. Our results revealed a statistically significant increased bladder cancerrisk for GSTT1 null genotype carriers with an odds ratio of 3.06 (95% confidence interval=1.39-6.74, p=0.006).Differences of CYP1A1, CYP1B1 and GSTM1 genotype frequencies were not statistically significant betweenpatients and controls. However, the specific combination of GSTM1 null, GSTT1 null, and CYP1B1 codon 119risk allele carriers and specific combination of GSTM1 present, GSTT1 null, and CYP1B1 432 risk allele carriersexhibited increased cancer risk in the combined analysis. We did not observe any association between differentgenotype groups and prognostic tumor characteristics of bladder cancer. Our results indicate that inheritedabsence of GSTT1 gene may be associated with bladder cancer susceptibility, and specific combinations ofGSTM1, GSTT1 and CYP1B1 gene polymorphisms may modify bladder cancer risk in the Turkish population,without any association being observed for CYP1A1 gene polymorphism and bladder cancer risk.     

Quantitative assessment of the association between CYP1A1 A4889G polymorphism and endometrial cancer risk

Cytochrome P450 1A1 (CYP1A1) A4889G polymorphism was supposed to be associated with endometrial cancer risk, but previous studies reported conflicting results. We therefore performed a meta-analysis of all relevant studies to get a comprehensive assessment of the association between CYP1A1 A4889G polymorphism and endometrial cancer risk. The pooled odds ratios (OR) with the corresponding 95 % confidence interval (95 % CI) was calculated to assess the association. Finally, ten studies with a total of 1,682 endometrial cancer cases and 2,510 controls were finally included into the meta-analysis. Meta-analysis of the total ten studies showed that CYP1A1 A4889G polymorphism was not associated with endometrial cancer risk (OR_{G versus A}?=?1.14, 95 % CI 0.83–1.57, P _OR?=?0.417; OR_{GG versus AA}?=?1.23, 95 % CI 0.70–2.18, P _OR?=?0.470; OR_{GG versus AA/AG}?=?1.03, 95 % CI 0.59–1.81, P _OR?=?0.919; OR_{GG/AG versus AA}?=?1.22, 95 % CI 0.82–1.81, P _OR?=?0.336). Subgroup analyses by ethnicity further showed that there was also no obvious association between CYP1A1 A4889G polymorphism and endometrial cancer risk in both Caucasians and Asians. Sensitivity analysis by excluding single study in turns showed that the pooled estimations were not stable. Therefore, evidence for currently available data suggests that CYP1A1 A4889G polymorphism is not associated with endometrial cancer risk. However, more studies with large number of participants are needed to further assess the association precisely.     

Cytochrome P450 1B1 gene polymorphisms and postmenopausal endometrial cancer risk.

Estrogen unopposed by progestins is a key factor in endometrial cancer etiology. Cytochrome P450 1B1 (CYP1B1), responsible for the 4-hydroxylation of estrogen, may be important in endometrial carcinogenesis, either as a regulator of estrogen availability or as a producer of potentially genotoxic estrogen metabolites. We investigated the association of CYP1B1 genotype and endometrial cancer risk in a population-based case-control study of postmenopausal Swedish women. We used the Expectation-Maximization algorithm to estimate the haplotype frequencies in the population and calculated odds ratios and 95% confidence intervals from conditional logistic regression models. In stratified analysis, we investigated the possible effects of CYP1B1 genotype on endometrial cancer risk in subgroups defined primarily by menopausal hormone use and also by body mass index, smoking, use of combined oral contraceptives, and family history. We genotyped 689 cases and 1,549 controls for the CYP1B1 single nucleotide polymorphisms m2, m3, and m4 and estimated the haplotype frequencies among controls to 0.086, 0.291, 0.452, and 0.169 for the CYP1B1*1, CYP1B1*2, CYP1B1*3, and CYP1B1*4 alleles, respectively. We found no evidence for an overall association between CYP1B1 genotype and endometrial cancer risk, nor was there any clear indication of gene-environment interaction.