RESUMEN
BACKGROUND: Single nucleotide polymorphisms (SNPs) in genes that act in intrinsic apoptosis pathway may modulate cancer susceptibility. This study investigated the roles of CASP9 c.-1339A>G (rs4645978) and CASP3 c.-1191A>G (rs12108497) SNPs on risk and behavior of head and neck (HN) squamous cell carcinoma (SCC). METHODS: DNA of 350 patients with HNSCC and 350 controls was analyzed by polymerase chain reaction method for genotyping. RESULTS: CASP3 c.-1191AG or GG genotype was more common in patients with HNSCC and oral cavity or oropharynx SCC than in controls; carriers of this genotype were under 2.15 and 2.81-fold increased risks of the respective tumors. CASP9 c.-1339AG or GG plus CASP3 c.-1191AG or GG genotypes were associated with oral cavity or oropharynx SCC early onset. CONCLUSION: These findings present, for the first time, preliminary evidence that inherited abnormalities related to CASP9 c.-1339A>G and CASP3 c.-1191A>G SNPs are determinants of HNSCC risk and clinical aspects.