KRAS and colorectal carcinoma: Our retrospective analysis of 1099 samples from Chinese CRC patients showed that the frequency of a KRAS mutation was 39.76 %, which is similar to the previously published data from Japan, the Netherlands, Germany, and the United States (37–43 %), but higher than those from Thailand, India, South Korea, Oman, and Australia (23–31 %) (Additional file 1: Table S1).