KRAS mutations serve a function in tumorigenesis of colorectal cancer (CRC) and guide the use of targeted drugs. However, the prognostic value of KRAS mutations and their subtypes remain controversial. The present study aimed to investigate the correlations between KRAS mutations and clinicopathological characteristics, and their prognostic significance in Chinese patients with metastatic CRC (mCRC). A total of 135 patients with mCRC were analyzed for KRAS mutations. Mutations in codon 12 and 13 were identified in 45 (33.3%) patients. Only 3 patients harbored a mutation of V600E. Compared with male patients, KRAS codon 12 mutations were more common in female patients (P<0.05). KRAS codon 13 mutations tended to arise in right-sided compared with left-sided colon cancer (P<0.05). Survival analysis was performed in 101 patients receiving primary tumor resection. Compared with KRAS codon 12 wild-type, codon 12 mutations were markedly correlated with a poorer survival (log-rank P=0.002). No prognostic significance was revealed in codon 13 mutations. In univariate analysis, mortality risk was significantly increased by subtypes of G12D and G12V [hazard ratio (HR) =2.313, 95% confidence interval (CI) =1.069-5.004, P=0.03; HR=2.621, 95% CI=1.057-6.497, P=0.04, respectively]. The results of the present study suggested that codon 12 mutations, in particular G12D and G12V, predicted a negative prognosis in Chinese patients with mCRC. These findings require further confirmation via prospective studies with larger samples.
Keywords: KRAS codon 12; KRAS mutations; colorectal cancer; overall survival; prognosis.