Deficient mismatch repair and RAS mutation in colorectal carcinoma patients: a retrospective study in Eastern China.

ABSTRACT: Objectives:To investigate the frequency and prognostic role of deficient mismatch repair (dMMR) and RAS mutation in Chinese patients with colorectal carcinoma. Methods:Clinical and pathological information from 813 patients were reviewed and recorded. Expression of mismatch repair proteins was tested by immunohistochemistry. Mutation analyses for RAS gene were performed by real-time polymerase chain reaction. Correlations of mismatch repair status and RAS mutation status with clinicopathological characteristics and disease survival were determined. Results:The overall percentage of dMMR was 15.18% (121/797). The proportion of dMMR was higher in patients <50 years old (p < 0.001) and in the right side of the colon (p < 0.001). Deficient mismatch repair was also associated with mucinous production (p < 0.001), poor differentiation (p < 0.001), early tumor stage (p < 0.05) and bowel wall invasion (p < 0.05). The overall RAS mutation rate was 45.88%, including 42.56% (346/813) KRAS mutation and 3.69% (30/813) NRAS mutation (including three patients with mutations in both). KRAS mutation was significantly associated with mucinous production (p < 0.05), tumor stage (p < 0.05) and was higher in non-smokers (p < 0.05) and patients with a family history of colorectal carcinoma (p < 0.05). Overall, 44.63% (54/121) dMMR tumors harbored KRAS mutation, however, dMMR tumors were less likely to have NRAS mutation. Moreover, dMMR, KRAS and NRAS mutation were not prognostic factors for stage I-III colorectal carcinoma. Conclusions:This study confirms that the status of molecular markers involving mismatch repair status and RAS mutation reflects the specific clinicopathological characteristics of colorectal carcinoma.

SUBMITTER: Zhang X 

PROVIDER: S-EPMC5804321 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature