The PIK3CA mutation (13.18%) was lower than some previous data, which ranged from 12.2 to 20.18%12, 35, 36, 42, 43, 44, ethnic population, various detection methods and whether rectum cancer involved may explain the difference, the PIK3CA mutation did not significantly associated with clinicopathological characteristics, which was consistent with reported results35, 43, 44. This evidence concerns the gene PIK3CA and rectal cancer.