Polymorphisms In DNA Repair Pathways Research Articles

Polymorphisms in the BER and NER pathways and their influence on survival and toxicity in never-smokers with lung cancer

Polymorphisms in DNA repair pathways may play a relevant role in lung cancer survival in never-smokers. Furthermore, they could be implicated in the response to chemotherapy and toxicity of platinum agents. The aim of this study was to evaluate the influence of various genetic polymorphisms in the BER and NER DNA repair pathways on survival and toxicity in never-smoker LC patients. The study included never-smokers LC cases diagnosed from 2011 through 2019, belonging to the Lung Cancer Research In Never Smokers study. A total of 356 never-smokers cases participated (79% women; 83% adenocarcinoma and 65% stage IV). Survival at 3 and 5 years from diagnosis was not associated with genetic polymorphisms, except in the subgroup of patients who received radiotherapy or chemo-radiotherapy, and presented with ERCC1 rs3212986 polymorphism. There was greater toxicity in those presenting OGG1 rs1052133 (CG) and ERCC1 rs11615 polymorphisms among patients treated with radiotherapy or chemo-radiotherapy, respectively. In general, polymorphisms in the BER and NER pathways do not seem to play a relevant role in survival and response to treatment among never-smoker LC patients.

Genetic variants in microRNA-binding sites of DNA repair genes as predictors of recurrence in patients with squamous cell carcinoma of the oropharynx.

The incidence of squamous cell carcinoma of the oropharynx (SCCOP) continues to rise because of increasing rates of human papillomavirus (HPV) infection. Inherited polymorphisms in DNA repair pathways may influence the risk of SCCOP development and the prognosis of SCCOP. We sought to determine whether polymorphisms in microRNA (miRNA)-binding sites within 3'-untranslated regions (3'UTRs) of genes in DNA repair pathways modulate the risk of SCCOP recurrence. We evaluated the associations between nine such polymorphisms and SCCOP recurrence in 1,008 patients with incident SCCOP using the log-rank test and multivariable Cox models. In an analysis of all the patients, patients with variant genotypes of BRCA1 rs12516 and RAD51 rs7180135 had better disease-free survival (log-rank, p = 0.0002 and p = 0.0003, respectively) and lower risk of SCCOP recurrence (hazard ratio [HR], 0.5, 95% confidence interval [CI], 0.2-0.8, and HR, 0.5, 95% CI, 0.3-0.9, respectively) than patients with common homozygous genotypes of the two polymorphisms after multivariable adjustment. Moreover, in tumor HPV16-positive patients, patients with variant genotypes of the same two polymorphisms also had better disease-free survival (log-rank, p = 0.004 and p = 0.003, respectively) and lower recurrence risk (HR, 0.2, 95% CI, 0.1-0.6, and HR, 0.2, 95% CI, 0.0-0.7, respectively) than patients with common homozygous genotypes of the two polymorphisms. No such significant associations were found for other polymorphisms. These findings support significant roles of BRCA1 rs12516 and RAD51 rs7180135 in modifying the risk of recurrence of SCCOP, particularly HPV16-positive SCCOP. However, these results must be validated in larger studies.

Genetic variability of DNA repair mechanisms influences treatment outcome of gastric cancer

The aim of the current study was to investigate the role of polymorphisms in DNA repair pathways on the clinical outcome of gastric cancer patients treated with platinum-based chemotherapy. A total of 380 gastric cancer patients treated with platinum-based chemotherapy were included in the present study. The genotypes of ERCC1 rs11615 (Asn118Asn) and rs3212986 (*197G>T), ERCC2 rs1799793 (Asn312Asp) and rs13181 (Lys751Gln), NBN rs1805794 (Gln185Gln) and rs1063054 (*1209A>C), RAD51 rs1801321 (−61G>T) and rs12593359 (*502T>G), and XRCC3 rs861539 (Thr241Met) were determined by polymerase chain reaction-restriction fragment length polymorphism, according to the manufacturer's instructions. The TC+CC genotypes of ERCC1 rs11615 and GA+AA genotypes of ERCC2 rs1799793 were found to be associated with improved response to chemotherapy, with an adjusted odds ratio of 1.66 (95% CI, 1.07–2.56) and 1.61 (95% CI, 1.05–2.49), respectively. Based on the results of Cox analysis, patients with TC+CC genotypes of ERCC1 rs11615 and GA+AA genotypes of ERCC2 rs1799793 exhibited a significantly decreased risk of mortality, with hazard ratios of 1.71 (95% CI, 1.06–2.72) and 1.97 (95% CI, 1.28–3.03), respectively. In conclusion, these results suggest that ERCC1 rs11615 and ERCC2 rs1799793 in the DNA repair pathways may be used as predictive factors of the clinical outcome in gastric cancer patients.

Lung Cancer Risk and Genetic Polymorphisms in DNA Repair Pathways: A Meta‐Analysis

Genetic variations in DNA repair genes are thought to modulate DNA repair capacity and are suggested to be related to lung cancer risk. We conducted a meta-analysis of epidemiologic studies on the association between genetic polymorphisms in both base excision repair and nucleotide excision repair pathways, and lung cancer. We found xeroderma pigmentosum complementation group A (XPA) G23A (odds ratio (OR) = 0.76, 95% confidence interval (CI) = 0.61–0.94), 8-oxoguanine DNA glycosylase 1 (OGG1) Ser326Cys (OR = 1.22, 95% CI = 1.02–1.45), and excision repair cross-complementing group 2 (ERCC2) Lys751Gln (OR = 1.27, 95% CI = 1.10–1.46) polymorphisms were associated with lung cancer risk. Considering the data available, it can be conjectured that if there is any risk association between a single SNP and lung cancer, the risk fluctuation will probably be minimal. Advances in the identification of new polymorphisms and in high-throughput genotyping techniques will facilitate the analysis of multiple genes in multiple DNA repair pathways. Therefore, it is likely that the defining feature of future epidemiologic studies will be the simultaneous analysis of large samples of cases and controls.