Correlation Analysis Of Mismatch Repair Protein Expression With Clinicopathological And Prognosis In Colon Cancer In Each Stage And Overall

Objective:1.To explore the status of MMR protein expression loss in patients with colon cancer,and the clinicopathological characteristics of dMMR phenotype in patients with colon cancer in general and at different stages;2.To explore the prognosis characteristics of patients with dMMR phenotype in each stage and overall.Methods:1.The first part of this study,1279 patients with colon cancer who received surgical treatment in the Department of Digestive Surgery,the First Affiliated Hospital of Air Force Military Medical University from January 2010 to December 2017 and met the discharge criteria were included.In the second part,some of these patients were followed up for a long time,and 334 patients with complete follow-up data and clinicopathological data were included in the study.2.According to the expression of MMR protein(MLH1,MSH2,MSH6,PMS2)detected by IHC,the patients were divided into two groups: the deficient mismatch repair (dMMR)group and the proficient mismatch repair(pMMR)group.The frequency distribution of dMMR and the clinicopathological characteristics and prognosis characteristics of dMMR phenotype in colon cancer patients were retrospectively analyzed.Results:1.In 1 279 colon cancer patients,the dMMR rate was 22.0%(282/1279),and the deletion rates of four MMR proteins MLH1,MSH2,MSH6 and PMS2 were 7.2%,5.6%,7.0% and 15.5%,respectively.Meanwhile,the combined deletion rates of MLH1+PMS2 and MSH2+MSH6 were 7.0% and 4.9%,respectively.dMMR frequency distribution in each stage is different: stageⅠis 24.8%(25/101),stage Ⅱ is 30.9%(182/589),stage Ⅲ is 13.0%(64/492),stage Ⅳ is 11.3%(11/97).2.Compared with pMMR group,patients in dMMR group were younger,had a higher proportion of right colon tumors,had a higher proportion of poorly differentiated tumors,had a longer maximal tumor diameter,tended to be bulge rather than infiltrate,had earlier TNM staging,and had a higher proportion of N0 and M0 patients(P<0.05).There was no significant difference between sex and T stage.3.In stage Ⅰ colon cancer patients,compared with pMMR group,dMMR group had a higher proportion of right colon tumors,had a higher proportion of poorly differentiated tumors.There were no significant differences in age,sex,tumor type and maximal tumor diameter.In stage Ⅱ colon cancer patients,compared with pMMR group,patients in dMMR group were younger,had a higher proportion of right colon tumors,had a higher proportion of poorly differentiated tumors,had a longer maximal tumor diameter,tended to be bulge rather than infiltrate,and the proportion of gender was no significant difference.In stage Ⅲ colon cancer patients,compared with pMMR group,dMMR group of patients were younger,had a higher proportion of right colon tumors,had a higher proportion of poorly differentiated tumors,had a longer maximal tumor diameter,sex and tumor gross type was no significant difference.In stage Ⅳ colon cancer patients,compared with pMMR group,dMMR group of patient’s age,sex,tumor location,degree of differentiation,tumor size,gross type,maximal tumor diameter had no significant difference.4.About prognosis,dMMR group has significantly better OS than pMMR group(67.41±2.73 months vs60.35±1.67 months,P=0.047),and the difference was statistically significant.5.In stage Ⅰ patients,there were no significant differences between two groups of OS time.In stage Ⅱ patients,dMMR group has better OS than pMMR group(77.61±1.02 months vs 65.66±2.15 months,P=0.001),and the difference was statistically significant.In stage Ⅲ patients,pMMR group has better OS than dMMR group (41.72±6.45 months vs 55.66±2.55 months,P=0.031),and the difference was statistically significant.In stage Ⅳ patients,dMMR group has better OS than pMMR group(44.68±14.30 months vs 29.93±5.72 months,P=0.399),but there is no statistically significant differences.Conclusion:1.There is a certain proportion of dMMR in colon cancer patients,and the distribution is different in different stages.2.dMMR phenotype of colon cancer is characterized by younger age,higher proportion of right colon tumors,poorly differentiation,longer maximal tumor diameter,more protuberant type,lower rate of lymph node metastasis and distant metastasis,and earlier TNM staging.In addition,the clinical characteristics of dMR phenotype of colon cancer are different in different stages.3.dMMR phenotype of colon cancer has a better prognosis than pMMR phenotype,and the prognosis characteristics of dMMR phenotype of colon cancer is different in different stages.