Glutathione S-Transferase P1 313 (A > G) Ile105Val Polymorphism Contributes to Cancer Susceptibility in Indian Population: A Meta-analysis of 39 Case-Control Studies

Revisiting Genetic Influence on Mercury Exposure and Intoxication in Humans: A Scoping Review

Human intoxication to mercury is a worldwide health problem. In addition to the type and length of exposure, the genetic background plays an important role in mercury poisoning. However, reviews on the genetic influence in mercury toxicity are scarce and not systematic. Therefore, this review aimed to systematically overview the most recent evidence on the genetic influence (using single nucleotide polymorphisms, SNPs) on human mercury poisoning. Three different databases (PubMed/Medline, Web of Science and Scopus) were searched, and 380 studies were found that were published from 2015 to 2022. After applying inclusion/exclusion criteria, 29 studies were selected and data on characteristics (year, country, profile of participants) and results (mercury biomarkers and quantitation, SNPs, main findings) were extracted and analyzed. The largest number of studies was performed in Brazil, mainly involving traditional populations of the Tapajós River basin. Most studies evaluated the influence of the SNPs related to genes of the glutathione system (GST, GPx, etc.), the ATP-binding cassette transporters and the metallothionein proteins. The recent findings regarding other SNPs, such as those of apolipoprotein E and brain-derived neurotrophic factor genes, are also highlighted. The importance of the exposure level is discussed considering the possible biphasic behavior of the genetic modulation phenomena that could explain some SNP associations. Overall, recommendations are provided for future studies based on the analysis obtained in this scoping review.

Microalgae as a Nutraceutical Tool to Antagonize the Impairment of Redox Status Induced by SNPs: Implications on Insulin Resistance

Microalgae represent a growing innovative source of nutraceuticals such as carotenoids and phenolic compound which are naturally present within these single-celled organisms or can be induced in response to specific growth conditions. The presence of the unfavourable allelic variant in genes involved in the control of oxidative stress, due to one or more SNPs in gene encoding protein involved in the regulation of redox balance, can lead to pathological conditions such as insulin resistance, which, in turn, is directly involved in the pathogenesis of type 2 diabetes mellitus. In this review we provide an overview of the main SNPs in antioxidant genes involved in the promotion of insulin resistance with a focus on the potential role of microalgae-derived antioxidant molecules as novel nutritional tools to mitigate oxidative stress and improve insulin sensitivity.

Association of GSTP1 p.Ile105Val (rs1695, c.313A > G) Variant with the Risk of Breast Carcinoma among Egyptian Women

Several reports examined the association of the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant with the elevated risk of multiple cancerous diseases involving breast carcinoma, but with inconclusive findings. The primary purpose of this study is to test the association of this essential variant with the risk of breast carcinoma among Egyptian females. This case-control study was conducted based on 200 participants involving 100 women diagnosed with breast carcinoma and 100 unrelated cancer-free controls from the same district. The genomic DNA for all participants was genotyped utilizing T-ARMS-PCR procedure. The frequencies of the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant indicated a statistically significant with the elevated risk of breast carcinoma under various genetic models, including allelic (OR = 2.48, P-value < 0.001) and dominant (OR = 2.36, P-value = 0.003) models. In conclusion, the GSTP1 p.Ile105Val (rs1695, c.313A > G) variant was considered as an independent risk factor for breast carcinoma among Egyptian women.

Evaluating the role of GSTP1 genetic polymorphism (rs1695, 313A>G) as a predictor in cyclophosphamide-induced toxicities

The association between Glutathione S-transferase Pi 1(GSTP1) genetic polymorphism (rs1695, 313A>G) and cyclophosphamide-induced toxicities has been widely investigated in previous studies, however, the results were inconsistent. This study was performed to further elucidate the association.A comprehensive search was conducted in PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wan Fang database up to January 5, 2020. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were used to estimate the association between GSTP1 rs1695 polymorphism and cyclophosphamide-induced hemotoxicity, gastrointestinal toxicity, infection, and neurotoxicity.A total of 13 studies were eventually included. Compared with the GSTP1 rs1695 AA genotype carriers, patients with AG and GG genotypes had an increased risk of cyclophosphamide-induced gastrointestinal toxicity (RR, 1.61; 95% CI, 1.18-2.19; P = .003) and infection (RR, 1.57; 95% CI, 1.00-2.48; P = .05) in the overall population. In the subgroup analyses, there were significant associations between GSTP1 rs1695 polymorphism and the risk of cyclophosphamide-induced myelosuppression (RR, 2.10; 95% CI, 1.60-2.76; P < .00001), gastrointestinal toxicity (RR, 1.77; 95%CI, 1.25-2.53; P = .001), and infection (RR, 2.01; 95% CI, 1.14-3.54; P = .02) in systemic lupus erythematosus (SLE) or lupus nephritis syndrome patients, but not in cancer patients.Our results confirmed an essential role for the GSTP1 rs1695 polymorphism in the prediction of cyclophosphamide-induced myelosuppression, gastrointestinal toxicity, and infection in SLE or lupus nephritis syndrome patients. More studies are necessary to validate our findings in the future.

Interaction of glutathione-s-transferase genotypes with environmental risk factors in determining susceptibility to head and neck cancer and treatment response and survival outcome

The present case-control study aimed to investigate the role of interaction of glutathione-s-transferase (GST) genotypes with environmental risk factors in determining susceptibility to head and neck squamous cell carcinoma (HNSCC) involving 1,250 cases and equal number of healthy controls. An increase in the risk of HNSCC and its subsites (larynx, pharynx, and oral cavity) was observed among the cases with null genotypes of GSTM1 (odds ratio [OR] = 1.87) or GSTT1 (OR = 1.39) while reduced risk (OR = 0.81) was observed the cases with variant genotype of GSTP1. Tobacco use in the form of smoking or chewing interacted multiplicatively with GSTM1 or GSTT1 to increase the risk several folds (3-10 folds) in HNSCC and its subsites. Alcohol use also increased the risk (2-3 folds) to HNSCC and its subsites in cases with null or variant genotypes of GSTs, though this risk was of lesser magnitude when compared to the tobacco users. A synergistic effect of both, tobacco smoking and alcohol drinking, led to several folds (25-folds) increased risk to HNSCC among the cases with null genotype of GSTM1 and GSTT1 when compared to nonsmokers and nondrinkers with wild genotype of GSTM1 and GSTT1 in controls. Furthermore, cases with variant genotypes of GSTP1 (Val/Val) showed superior treatment response with improved survival rate and lower risk of death when compared to the patients with wild type genotype (Ile/Ile). The data suggest that though polymorphism in GSTs may be a modest risk factor for determining HNSCC risk, gene-environment interactions significantly modify the susceptibility to HNSCC by several folds.