OBJECTIVETo investigate the mutation rate and types of KRAS gene in colorectal carcinoma of Chinese patients, and to document the regional distribution of the mutation.

METHODSA total of 6 364 colorectal carcinoma tumor specimens were obtained from 27 provinces and autonomous regions in China from 2009 to 2013. Pyrosequencing was used to detect mutations in codons 12 and 13 of KRAS gene. The mutation types of KRAS and the difference of regional distribution were statistically analyzed.

RESULTSKRAS mutation rate in Chinese colorectal carcinoma patients was 37.43 % (2 382/6 364). Ten types of single-base mutations of KRAS codons 12 and 13 were detected, including six common types: 12GGT > GAT (14.77%), 13GGC > GAC (8.19%), 12GGT > GTT (7.89%), 12GGT > TGT (2.20%), 12GGT > AGT (2.00%), and 12GGT > GCT (1.48%). Other four less occurring mutation types (<1%) included 12GGT > CGT, 13GGC > TGC, 13GGC > CGC, and 13GGC > AGC. In addition, 8 other mutation types were identified in 13 tumor samples. The rates of KRAS mutation in patients from different regions were between 35.68% and 38.04% and no significant differences were observed (P > 0.05).

CONCLUSIONSAbundant mutation types of KRAS gene exist in colorectal cancers among Chinese patients. The six common mutation types occur with a frequency of not less than 1%. There are no significant differences of KRAS mutation rate among Chinese patients from various areas. Pyrosequencing provides a rapid and accurate method of KRAS mutation detection for clinical application.

Aged ; Asian Continental Ancestry Group ; China ; Codon ; Colorectal Neoplasms ; genetics ; Female ; Genes, ras ; Humans ; Male ; Middle Aged ; Mutation ; Mutation Rate