Effect of Arg399Gln single-nucleotide polymorphism in XRCC1 gene on survival rate of Indian squamous cell head-and-neck cancer patients.

ABSTRACT

BACKGROUND: Head-and-neck squamous cell carcinoma (HNSCC) is one of the most common cancers that contribute to 20%-40% of all cancer incidences in India. Indian patients with HNSCC are mostly associated with tobacco usage and may have different genetic alterations compared with Western patients who are mostly associated with human papillomavirus infection. Polymorphisms in DNA repair genes are correlated to individuals' susceptibility and progression of cancer. XRCC1 is a DNA repair enzyme. MATERIALS AND METHODS: In the present prospective study, Indian population of HNSCC patients (n = 45) were screened for Arg399Gln variant of XRCC1 using polymerase chain reaction-restriction fragment length polymorphism technique, prospective evaluation of the patients was done after treatment, and the single-nucleotide polymorphism results were correlated to survival functions. RESULTS: Out of 45 patients, 28 patients were Arg/Arg, 12 patients were Arg/Gln, and 5 patients were Gln/Gln. Overall survival for the entire cohort and Arg/Arg, Arg/Gln, and Gln/Gln cohort was 36.3 (95% confidence interval [CI] 33-39.5), 38.6 (95% CI 35.3-41.9), 35.8 (95% CI 28.6-42.9), and 26.4 (95% CI 13.7-39.1) months (P = 0.097), respectively. Progression-free survival (PFS) of the entire patient cohort and Arg/Arg, Arg/Gln, and Gln/Gln cohort was 35.2 (95% CI 31.4-39.1), 38.2 (95% CI 34.3-42.1), 32.7 (95% CI 26.2-39.1), and 22.3 (95% CI 9.4-35.3) (P = 0.061), respectively. CONCLUSIONS: This study suggests that HNSCC patients with Gln substitution in place of Arg at position 399 (both homozygous and heterozygous) in XRCC1 protein have significantly inferior survival functions, higher recurrence rate, and events after radical treatment.