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

Objectives: To investigate the frequency and prognostic role of deficient mismatch repair (dMMR) and 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 gene were performed by real-time polymerase chain reaction. Correlations of mismatch repair status and 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 ( < 0.001) and in the right side of the colon ( < 0.001). Deficient mismatch repair was also associated with mucinous production ( < 0.001), poor differentiation ( < 0.001), early tumor stage ( < 0.05) and bowel wall invasion ( < 0.05). The overall mutation rate was 45.88%, including 42.56% (346/813) mutation and 3.69% (30/813) mutation (including three patients with mutations in both). mutation was significantly associated with mucinous production ( < 0.05), tumor stage ( < 0.05) and was higher in non-smokers ( < 0.05) and patients with a family history of colorectal carcinoma ( < 0.05). Overall, 44.63% (54/121) dMMR tumors harbored mutation, however, dMMR tumors were less likely to have mutation. Moreover, dMMR, and 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 mutation reflects the specific clinicopathological characteristics of colorectal carcinoma.