Polymorphisms in biotransformation and DNA repair genes, and survival on head and neck squamous cell carcinoma

Objective: This study analyzed the association between xenobiotic metabolism and DNA repair gene polymorphisms and overall survival (OS) and disease-free survival (DFS) in patients diagnosed with HNSCC in a Brazilian population. Methods: Retrospective study included 91 patients with a confirmed diagnosis of HNSCC. A total of 7 genes were analyzed: XRCC1, HOGG1, CYP1A1, GSTM1, GSTT1, GSTP1 and NAT2. Results: Regarding OS, the largest mean differences were observed comparing GSTT1 rs71748309 null and GSTT1 rs71748309 non-null genotypes (p=0.050). In the gene-gene interaction analysis, the higher difference to OS was observed to the combined genotypes of the GSTM1 rs4025935 and GSTT1 rs71748309 (p=0.286). Regarding DFS, the largest mean differences were observed comparing GSTT1 rs71748309 null and GSTT1 rs71748309 non-null genotypes (p=0.060) and to the combined genotypes of the GSTM1 rs4025935 and GSTT1 rs71748309 (p=0.313). Conclusion: None of the polymorphisms evaluated in xenobiotic metabolism or DNA repair genes were significantly associated with HNSCC survival in our population. Confirmation of these results in larger studies is required.