Cytochrome P450 1A1 Ile462Val polymorphism and oral carcinoma risk: an updated meta-analysis including 1,515 cases and 2,233 controls

Does CYP2E1 RsaI/PstI polymorphism confer head and neck carcinoma susceptibility?: A meta-analysis based on 43 studies

BACKGROUND

Previous reports showed that CYP2E1 RsaI/PstI polymorphism may be a risk factor for cancers. Published meta-analyses in 2010 and 2011, respectively, on the relationship of CYP2E1 RsaI/PstI polymorphisms with the susceptibility to head and neck carcinoma (HNC) have generated inconsistent results. Thus, this study aimed to conduct an updated meta-analysis involving published studies up to Nov 2015 to get a more confidential result.

METHODS

Eligible studies up to Nov 2015 were retrieved and screened. Data were extracted and a quantitative meta-analysis was conducted. Subgroup analyses on ethnicity, source of controls, sample size, genotyping method, smoking status, and drinking status were also performed.

RESULTS

Forty-one publications including a total of 43 case-control studies were selected for analysis. The overall data under a homozygote comparison model indicated a significant association of CYP2E1 RsaI/PstI polymorphisms with HNC risk (c2c2 vs c1c1: odds ratio [OR] = 1.97; 95% confidence interval [CI] = 1.53-2.53). Similar results were observed in the Asian subgroup (c2c2 vs c1c1: OR = 1.98; 95%CI = 1.51-2.60; c2 vs c1: OR = 1.20; 95%CI = 1.03-1.39) and mixed population (c2 vs c1: OR = 1.41; 95%CI = 1.06-1.86) when the data were stratified by ethnicities. Interestingly, increased cancer risk only was shown among never-smokers (c2c2+c1c2 vs c1c1: OR = 1.44; 95%CI = 1.05-1.98) but not ever-smokers.

CONCLUSION

CYP2E1 RsaI/PstI polymorphisms may modify the susceptibility to HNC, particularly among Asians, mixed population, and never-smokers. Future large and well-designed studies are needed to verify this conclusion.

CYP1A1 Ile462Val polymorphism as a risk factor in cervical cancer development in the Polish population

Background and objective

There are inconsistent data of the cytochrome P450 1A1 (CYP1A1) Ile462Val (rs1048943) single nuclear polymorphism (SNP) as a genetic susceptibility factor for cervical cancer in various populations. Moreover, little is known about the interaction of this SNP with other risk factors, including contraceptive use, postmenopausal status, parity, and tobacco smoking.

Methods

Polymerase chain reaction-restriction fragment length polymorphism was used to study the prevalence of the CYP1A1 Ile462Val SNP in women with cervical cancer (n = 456) and controls (n = 495).

Results

Logistic regression analysis adjusting for age, parity, oral contraceptive use, tobacco smoking, and menopausal status demonstrated that that the CYP1A1 Ile/Val polymorphism was not associated with an increased risk of cervical cancer in all patients. The adjusted odds ratio (OR) for patients with the Ile/Val genotype vs. Ile/Ile genotype was 1.539 (95 % confidence interval [CI] 0.932–2.541, p = 0.091). However, an increase in cervical cancer risk was seen among patients with a positive history of tobacco smoking and parity. The adjusted OR for positive history of tobacco smoking with the Ile/Val vs. Ile/Ile genotypes was 2.978 (95 % CI 1.382–6.418, p = 0.0052). The adjusted OR for parity with the Ile/Val vs. Ile/Ile genotype was 1.739 (95 % CI 1.006–3.009, p = 0.0472).

Conclusion

Our genetic study suggests that the CYP1A1 Ile462Val SNP may be a risk factor for cervical cancer among patients with a positive history of tobacco smoking and parity.

Association between CYP1A1 Ile462Val Polymorphism and Oral Squamous Cell Carcinoma Susceptibility: Evidence from 13 Investigations

CYP1A1 Ile462Val polymorphism might play a key role in pathogenesis of oral squamous cell carcinoma (OSCC). Many case-control studies have investigated the association between CYP1A1 Ile462Val polymorphism and OSCC susceptibility. However, the conclusions are inconsistent. To aim a convincible conclusion, we carried out a meta-analysis to systematically evaluate the association of CYP1A1 Ile462Val polymorphism with OSCC susceptibility. We searched Pubmed, Web of Science, Ovid and Embase databases for available publications. The odds ratio (OR) with the corresponding 95% confidence interval (95% CI) was carried out to estimate the association. A total of 13 papers including 1468 cases and 2183 controls were included, a significant increased OSCC risk was observed in recessive model (OR=1.64, 95% CI=1.08-2.49), but not other genetic models. Our results suggest that the homozygous variant of CYP1A1 Ile462Val might be a risk factor of OSCC.

Cytochrome P450 in Cancer Susceptibility and Treatment

Cytochrome 450 (CYP450) designates a group of enzymes abundant in smooth endoplasmic reticulum of hepatocytes and epithelial cells of small intestines. The main function of CYP450 is oxidative catalysis of various endogenous and exogenous substances. CYP450 are implicated in phase I metabolism of 80% of drugs currently in use, including anticancer drugs. They are also involved in synthesis of various hormones and influence hormone-related cancers. CYP450 genes are highly polymorphic and their variants play an important role in cancer risk and treatment. Association studies and meta-analyses have been performed to decipher the role of CYP450 polymorphisms in cancer susceptibility. Cancer treatment involves multimodal therapies and evaluation of CYP450 polymorphisms is necessary for pharmacogenetic assessment of anticancer therapy outcomes. In addition, CYP450 inhibitors are being evaluated for improved pharmacokinetics and oral formulation of several anticancer drugs.

CYP1A1 Ile462Val polymorphism and colorectal cancer risk in Polish patients

Colorectal cancer (CRC) is an epidemiological problem of a great importance in Poland; each year approximately 14,600 new cases of the disease are diagnosed. Mortality associated with CRC reaches approximately 10,400 cases per year (according to the National Cancer Registry). The 5-year survival rate is approximately 25 %, which is one of the lowest rates in Europe. The etiology of sporadic colorectal cancer (CRC) is multifactorial and has been attributed to an interplay between both environmental and genetic risk factors. In addition, there is a general consensus that genetic factors may modulate the influence of environmental insults. Following these assumptions, we performed a study on widely described polymorphisms in xenobiotic-metabolizing enzymes and DNA repair genes which may influence individual susceptibility to cancer. We selected five candidate polymorphisms in following genes: ERCC1 Asp118Asn (rs11615), XPC i11C/A (rs2279017), XRCC3 Met241Thr (rs861539) CYP1A1 Ile462Val (rs1048943) and NAT2 A803G (rs1208) and assessed the importance of chosen SNPs on groups consisting of 478 CRC patients and 404 controls. Only CYP1A1 Ile462Val was statistically significant in CRC patients over 50 years old: OR 2.05 (1.29–3.28); p = 1.25E−02 and this association was more pronounced in the female group of CRC patients after the age of 50: OR 2.72 (1.43–5.14); p = 1.14E−02.

Generation of reactive oxygen species by polyenylpyrroles derivatives causes DNA damage leading to G2/M arrest and apoptosis in human oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) accounts for 5.8% of all malignancies in Taiwan and the incidence of OSCC is on the rise. OSCC is also a common malignancy worldwide and the five-year survival rate remains poor. Therefore, new and effective treatments are needed to control OSCC. In the present study we have investigated the efficacy and associated mechanisms of polyenylpyrroles and their analogs in both in vitro cell culture and in vivo nude mice xenografts. Auxarconjugatin B (compound 1a) resulted in cell cycle arrest in the G2/M phase and caspase-dependent apoptosis in OEC-M1 and HSC-3 cells by activating DNA damage and mitochondria dysfunction through the loss of mitochondrial membrane potential, release of cytochrome c, increase in B-cell lymphoma-2-associated X protein level, and decrease in B-cell lymphoma-2 level. Compound 1a-induced generation of intracellular reactive oxygen species through cytochrome P450 1A1 was identified as a major mechanism of its effect for DNA damage, mitochondria dysfunction and apoptosis, which was reversed by antioxidant N-acetylcysteine as well as cytochrome P450 1A1 inhibitor and specific siRNA. Furthermore, compound 1a-treated nude mice showed a reduction in the OEC-M1 xenograft tumor growth and an increase in the caspase-3 activation in xenograft tissue. These results provide promising insights as to how compound 1a mediates cytotoxicity and may prove to be a molecular rationale for its translation into a potential therapeutic against OSCC.

The association between the poly(A) polymorphism in the VDR gene and cancer risk: a meta-analysis

The poly(A) polymorphism (L/S) in the VDR gene has been implicated in susceptibility of cancer, but a number of studies have reported inconclusive results. The aim of this study is to investigate the relationship between the poly(A) polymorphism in the VDR gene and cancer risk by meta-analysis. We searched PubMed database, EMBASE database, CNKI database, and Wanfang database, covering all studies until January 22, 2013. Statistical analysis was performed by using the software Revman4.2 and STATA 10.0. A total 8,186 cancer cases and 8,685 controls in 19 case-control studies from 15 studies were identified for data analysis. The results suggested that the S allele carriers (SS+SL) did not have an increased or decreased risk of cancer when compared with the homozygote LL carriers (odds ratio (OR) =0.96, 95 % CI=0.87-1.06, P=0.43 for SS+SL vs. LL). In addition, in the subgroup analysis by ethnicity and cancer type, no significant association was found among Caucasians, African-Americans, prostate cancer, or breast cancer. This current meta-analysis suggested that the poly(A) polymorphism in the VDR gene may not contribute to the risk of cancer. Future studies are needed to validate our findings.

Functional CYP1A1 genetic variants, alone and in combination with smoking, contribute to development of head and neck cancers

CYP1A1 plays an essential role in pathogenesis of head and neck cancers. Functional CYP1A1 Ile462Val and MspI single nucleotide polymorphisms (SNP) are considered to have significant effects on risk of head and neck cancers. Several case-control studies have examined how these genetic polymorphisms are involved in development of this group of malignancies, but the conclusions are inconsistent. Therefore, we conducted this meta-analysis to systematically examine the associations between these functional genetic variants and head and neck cancer risk. A total of 28 studies are eligible for CYP1A1 Ile462Val SNP (4639 patients and 4701 controls), and 22 studies for MspI SNP (4168 patients and 4638 controls). Pooled odds ratios (ORs) and the 95% confidence interval (95% CI) were appropriately calculated using either fixed-effect model or random-effect model. There was no association between Ile462Val polymorphism and head and neck cancer risk (OR = 1.23, 95% CI = 0.99-1.53, P = 0.062). However, in a stratified analysis, a statistically significant correlation between this SNP and pharyngeal cancer risk was observed (OR = 1.76, 95% CI = 1.32-2.33, P < 0.001). For MspI SNP, our data indicated that carriers of TC and CC genotypes had a 34% increased risk to develop head and neck cancers compared to TT carriers (95% CI = 1.15-1.57, P < 0.001). This effect was even more pronounced in smokers (OR = 2.98, 95% CI = 1.69-5.26, P < 0.001), demonstrating that gene-smoking interaction intensifying carcinogenesis may exist. These findings reveal that the functional CYP1A1 MspI genetic variant, alone and in combination with smoking, plays a more important role in pathogenesis of head and neck cancers.