Abstract: Objective To investigate mutation rate and types of KRAS gene in colorectal carcinoma, and to analysis the relationship between KRAS gene mutation and clinicopathological parameters in patients with colorectal carcinoma（CRC）. Methods Scorpions Amplification Refractory Mutation System（ARMS） fluorescence quantitative PCR was performed to detect the mutations in codons 12 and 13 of KRAS gene and to correlate between clinicopathological characteristics and the presence of various KRAS gene mutations of colorectal carcinoma. Results KRAS mutations were identified in 518 patients(42.92%)，including G12D(197cases, 16.32%)，G12V(125cases, 10.36%)，G12C(40cases, 3.31%)，G12S(29cases, 2.40%)，G12A(21cases, 1.74%)，G12R(7cases, 0.58%)，13D(117cases, 9.69%). Female patients had a higher KRAS gene mutation rate than male (46.21%, 238/515vs.40.46%, 280/692, P<0.05). KRAS mutation was significantly higher in right colon cancer（46.45%，131/282）and in rectal cancer（44.50%，255/573）than that in left colon cancer（37.50%，132/352）（P<0.05，P<0.05）. Conclusion There are many types of KRAS mutations in colorectal cancer, and many mutation types exist simultaneously.The detection rate of KRAS mutation is higher in female CRC patients than the males. The detection rate of KRAS mutation was significantly higher in right colon cancer and in rectal cancer than that in left colon cancer.

Key words: Key Word：Colorectal neoplasms, DNA mutational analysis, genes, ras, Polymerase chain reaction