Clinicopathologic Features And Prognostic Value Of DNA Mismatch Repair Protein Expression Patterns In Stage Ⅱ/Ⅲ Colorectal Cancer

Objective:The purpose of this study was to evaluate the relationship between clinicopathological features and MMR status in patients with stage Ⅱ/ Ⅲ colorectal malignancy and the relationship between MMR status and the efficacy of oxaliplatin combined with fluorouracil adjuvant chemotherapy.Methods:In strict accordance with the inclusion and exclusion criteria,476 patients who underwent radical resection of colorectal cancer in the Second Hospital of Jilin University from December 2016 to December 2018 were selected as the study subjects,and their medical records were collected and followed up according to the follow-up plan.Results:In our study,the incidence of mismatched repair protein defect（d MMR）malignancy was 13.2%（63/476）.Further analysis of DMMR CRC subtype found that among all CRC cases,MLH1 deletion was found in 31 cases（6.6%）,PMS2 deletion in37 cases（7.9%）,MSH2 deletion in 16 cases（3.4%）,MSH6 deletion in 29 cases（6.2%）.There were 29 cases of MLH1/PMS2 combined deletion（6.2%）,11 cases of MSH2/MSH6 combined deletion（2.4%）,and 3 cases of MLH1/PMS2/MSH6 combined deletion（0.1%）.114 pMMR CRC patients had tumors located in the proximal colon,and 38 d MMR CRC patients had tumors located in the proximal colon,Statistically significant differences（27.6% vs.60.3%;P < 0.01）.In addition,there were significant differences.In tumor size,lymphatic metastasis,pathological classification and degree of differentiation.In a multivariate Cox regression model,postoperative adjuvant chemotherapy and mismatched repair protein loss were associated with better prognosis in stage Class Ⅱ/Ⅲ colorectal cancer patients（HR 0.47,95%CI 0.30-0.74,P=0.001;HR 0.34,95% CI 0.14-0.79,P =0.013）.However,adjuvant Chemotherapy based on oxaliplatin and fluorouracil did not prolong the OS of d MMR CRC（P = 0.182）.Conclusions:MMR protein was significantly correlated with tumor stage,tumor location and tumor Size.MMR Protein is an independent prognostic marker in patients with stage ⅡCRC,but colorectal cancer patients with mismatched repair protein deficiency do not appear to benefit from oxaliplatin plus fluorouracil adjuvant chemotherapy.