Our results showed that 3 SNPs (CTNNB1 rs1880481 and rs3864004, and GSK3β rs375557) were correlated to the efficacy of RT, and 2 SNPs (APC rs454886 and GSK3β rs375557) were correlated with acute grade 3–4 radiation-induced toxic reactions in NPC patients. The gene discussed is GSK3B; the disease is nasopharyngeal carcinoma.