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.