Analysis of rs25487 (Arg399Gln) in XRCC1 in Sudanese Diagnosed with Nasopharyngeal Carcinoma and Its Possible Risk Factors

Abstract

Nasopharyngeal carcinoma (NPC) is a multifactorial malignancy influenced by genetic susceptibility and environmental exposures. The XRCC1 Arg399Gln (rs25487) polymorphism has been associated with NPC risk in several populations; however, evidence from African populations remains scarce. This study investigated the association between the XRCC1 Arg399Gln polymorphism and NPC susceptibility in a Sudanese population. A case-control study was conducted including 71 patients with histopathologically confirmed NPC and 71 cancer-free controls recruited through the Upper Aerodigestive Tract Biobank. Genomic DNA was extracted from peripheral blood samples, and the XRCC1 Arg399Gln polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Associations between genotype distributions, genetic models, and NPC risk were evaluated using crude odds ratios (ORs) with 95% confidence intervals (CIs). Environmental exposures, including cigarette smoking, alcohol consumption, and intake of salted fish “Kajeek” , were also compared between cases and controls. Genotype frequencies did not differ significantly between cases and controls. Compared with the Arg/Arg genotype, neither the Arg/Gln genotype (OR = 0.73, 95% CI: 0.34-1.54; P = 0.400) nor the Gln/Gln genotype (OR = 0.63, 95% CI: 0.21-1.91; P = 0.410) was associated with NPC susceptibility. No significant associations were observed under dominant, recessive, or allelic genetic models. Cigarette smoking and alcohol consumption were not associated with NPC risk, while salted fish intake showed a borderline association (OR = 2.28, 95% CI: 0.99-5.23; P = 0.055). The study had approximately 80% power to detect an odds ratio of 2.6 or greater. No significant association was observed between the XRCC1 Arg399Gln polymorphism and NPC susceptibility in this Sudanese population. Although limited by sample size, this study provides the first data on the distribution of the XRCC1 Arg399Gln polymorphism among Sudanese patients with NPC. It contributes valuable baseline evidence from an understudied African population.