Glutathione-S-transferase (GSTM1, GSTT1) null phenotypes and risk of lung cancer in a Korean population

Cytokinesis-block micronucleus cytome (CBMN-CYT) assay and its relationship with genetic polymorphisms in welders

Fumes generated in the welding process are composed of micrometric and nanometric particles that form when metal fumes condense. The International Agency for Research on Cancer established that many compounds derived from the welding process are carcinogenic to humans. Still, there are few studies related to the role of genetic polymorphisms. This work aimed to analyze the influence of OGG1 Ser326Cys, XRCC1 Arg280His, XRCC1 Arg194Thr, XRCC1 Arg399Gln, XRCC3 Thr241Met, GSTM1, and GSTT1 gene polymorphisms on DNA damage of 98 subjects occupationally exposed to welding fumes and 100 non exposed individuals. The results showed that individuals exposed to welding fumes with XRCC3 Thr241Thr, XRCC3 Thr241Met, and GSTM1 null genotypes demonstrated a significantly higher micronucleus frequency in lymphocytes. In contrast, individuals with XRCC1 Arg399Gln and XRCC1 Gln399Gln genotypes had significant levels of NPBs. OGG1 326 Ser/Cys, OGG1 326 Cys/Cys, XRCC1 194Arg/Thr, XRCC1 194Thr/Thr, and GSTT1 null genotypes exhibited significantly higher apoptotic values. Also, XRCC1 194Arg/Trp, XRCC1 194Thr/Thr, and GSTM1 null genotype carriers had higher necrotic levels compared to XRCC1 194Arg/Arg and GSTM1 nonnull carriers. Compositional analysis revealed the presence of iron, manganese, silicon as well as particles smaller than 2 μm that adhere to each other and form agglomerates. These results may be associated with a mixture of components, such as nitrogen dioxide, carbon monoxide, and metallic fumes, leading to significant DNA damage and cell death processes. These findings demonstrated the importance of the association between individual susceptibility and DNA damage levels due to occupational exposure to welding fumes; and constitute one of the first studies carried out in exposed workers from Colombia.

Combined effects of glutathione S-transferase M1 and T1 polymorphisms on risk of lung cancer: Evidence from a meta-analysis

Many studies have reported an association between the glutathione S-transferase M1 null and T1 null polymorphisms and lung cancer risk. However, the combined effects of GSTM1 null and GSTT1 null polymorphisms have not been reported previously. We, therefore, performed a meta-analysis to investigate the combined effects. 40 publications with 44 case–control studies were selected in the meta-analysis, including 13,706 cases and 13,093 controls. Significant association was observed between the combined effects of GSTM1 and GSTT1 polymorphisms and lung cancer risk when all the eligible studies were pooled into the meta-analysis. When we performed subgroup analysis, significantly increased lung cancer risk was observed in Caucasians (− − vs. + +: OR = 1.23, 95% CI: 1.07 to 1.41), Asians (− − vs.− +: OR = 1.24, 95% CI: 1.10 to 1.41; recessive model: OR = 1.45, 95% CI: 1.19 to 1.77; dominant model: OR = 1.53, 95% CI: 1.24 to 1.90), Indians (− − vs. + +: OR = 2.53, 95% CI: 1.61 to 3.98; recessive model: OR = 1.69, 95% CI: 1.07 to 2.67; dominant model: OR = 2.11, 95% CI: 1.36 to 3.28), hospital-based studies, and population-based studies. In summary, this meta-analysis indicates that the combined effects of the GSTM1 and GSTT1 polymorphisms are associated with increased lung cancer risk in Asians, Caucasians, and Indians.

RTN4 3'-UTR insertion/deletion polymorphism and susceptibility to non-small cell lung cancer in Chinese Han population

Nogo protein, encoded by gene reticulon-4 (RTN4), includes three major isoforms by different splicing, named Nogo-A Nogo-B and Nogo-C. Nogo proteins play an important role in the apoptosis of cells, especially in tumor cells. RTN4 single nucleotide polymorphisms (SNPs) can influence the efficiency of transcription and translation thus being related with an individual's predisposition to cancer. The CAA insertion/deletion polymorphism (rs34917480) within RTN4 3'-UTR has been reported to be associated with many cancer types. In order to investigate the relationship between this polymorphism and susceptibility to non-small cell lung cancer (NSCLC) in the Chinese population, we conducted the present case-control study including 411 NSCLC patients and 471 unrelated healthy controls. The genotype distributions were significantly different between cases and controls (p=0.014). We found that the del allele could significantly increase NSCLC risk (ins/ins vs ins/del: p=0.007, OR 1.46, 95%CI=1.11-1.93; dominant model: p=0.004, OR 1.47, 95%CI=1.13-1.92 and allele model: p=0.008, OR 1.35, 95%CI=1.08-1.67). This association was stronger in participants over 60 years old, males and smokers. We therefore conclude that the CAA insertion/deletion polymorphism (rs34917480) contributes to non-small cell lung cancer risk in Chinese population. Age, sex and environmental exposure are also related to carcinogenic effects of rs34917480.

Glutathione S-transferase θ1 polymorphism contributes to lung cancer susceptibility: A meta-analysis of 26 case-control studies

The GSTT1 gene encodes a key enzyme involved in the metabolism of xenobiotics and its polymorphisms have been associated with individual susceptibility to various malignancies. Numerous molecular epidemiological studies have been performed to investigate the association between GSTT1 gene polymorphisms and lung cancer susceptibility; however, the results of previous studies were inconsistent. Therefore, the aim of the present study was to conduct a meta-analysis in order to derive a more precise estimation of the association in the East Asian populations. The meta-analysis included 7,415 lung cancer cases and 6,084 controls from 26 published studies in East Asia, which were selected from the PubMed and China National Knowledge Infrastructure databases, up to March 20, 2014. Using crude odds ratios (ORs) with 95% confidence intervals (CIs), a statistically significant association was identified between the GSTT1 null genotype and lung cancer in the East Asian populations (OR=1.17; 95% CI, 1.09–1.25; P_{heterogeneity}=0.003). Furthermore, subgroup analyses revealed that the lung cancer risk in smokers carrying the GSTT1 null genotype was significantly increased compared with non-smokers (OR=1.71; 95% CI, 1.04–2.81; P_{heterogeneity}=0.002). Thus, the GSTT1 null genotype may increase the risk of lung cancer among the East Asian populations.

Glutathione S-transferase T1 and M1 polymorphisms and risk of uterine cervical lesions in women from central Serbia

The aim of this study was to investigate the frequencies of GSTT1 and GSTM1 deletion polymorphisms in newly-diagnosed patients with uterine cervical lesions from central Serbia. Polymorphisms of GST genes were genotyped in 97 patients with cervical lesions and 50 healthy women using a multiplex polymerase chain reaction (PCR). The GSTM1 null genotype was significantly more prominent among the patients than in controls (74.2% vs 56.0%), the risk associated with lesions being almost 2.3-fold increased (OR=2.26, 95%CI=1.10-4.65, p=0.03) and 3.17-fold higher in patients above >45 years old (95%CI=1.02-9.79, p=0.04). The analysis of the two genotypes demonstrated that GSTM1 null genotype significantly increased risk only for low grade squamous intraepithelial lesion-LSIL (OR=2.81, 95%CI=1.03-7.68, p=0.04). GSTT1 null genotype or different genotype combinations were not found to be risk factors, irrespective to lesion stages, age or smoking. We found that the risk of cervical lesions might be significantly related to the GSTM1 null genotype, especially in women aged above 45 years. Furthermore, the GSTM1 polymorphism might have greater role in development of early stage lesions.