| Objective: Objective of this sduty was to investigate the clinicopathological characteristics of stage ?-III colorectal cancer(CRC)patients with mismatch repairdeficiency(dMMR).Methods: A retrospective analysis of 61 patients with stage ?-? CRC who underwent radical resection from May 2017 to June 2019 at Shenjing Hospital of China Medical University were done,all of whom were confirmed by pathology and immunohistochemistry as dMMR type.A total of 183 stage ?-? CRC patients with proficient mismatch repair(pMMR)protein from the same period were randomly selected as a control group.The differences in the clinicopathological characteristics of the two groups were statistically analyzed.The t-test or wilcoxon rank sum test was used to compare the differences between the means.Chi-square test or Fisher's exact probability method were used to compare the differences between rates.Results:(1)There were significant differences between the dMMR and pMMR CRC groups in age,sex,site of onset,maximum diameter of tumor,T stage,tumor differentiation,and histological type(P < 0.05).Patients under 55 years old accounted for32.8% of the dMMR group,significantly higher than the 15.8% in the pMMR group;and the difference was statistically significant(P < 0.01).The female proportion of the dMMR group was 54.1%,significantly higher than the 38.3% in the pMMR group(P <0.05).63.9% of CRC occurred in the right hemicolon in the dMMR group,significantly higher than the 18.6% in the pMMR group(P < 0.01).The median diameter and quartile interval of the maximum tumor diameter were 6.0(4.0;7.0)cm in the dMMR group,significantly larger than the 4.5(3.5;5.5)cm in the pMMR group(P < 0.01).As for the T stage,62.3% of the dMMR group had T4 tumors,higher than the 21.9% in the pMMR group(P < 0.01).41.0% of the dMMR group patients had poorly differentiated tumors,higher than the 10.9% in the pMMR group(P < 0.01).Histologically,the proportion of specialhistologic adenocarcinoma was 23.0% in the dMMR group,significantly higher than the 8.2% in the pMMR group.(2).There was no significant difference between the two groups in the presence of nerve vessel invasion,the presence of cancer nodules,the N stage and TNM stage.In the dMMR group,there were 41 patients with PMS2/MLH1 deletion,accounting for 66.13%,and 21 with MSH2/MSH6 deletion,accounting for33.87%.Among them,5 cases were simply missing PMS2,accounting for 8.06%;16cases were missing for MSH2 and MSH6,accounting for 25.81%;5 cases were missing MSH6 alone,accounting for 8.06%;34 cases were missing for PMS2 and MLH1,accounting for 54.84%;and only 2 cases were positive for the MSH6 expression,accounting for 3.23%.(3).No patients were missing MLH1 expression alone,missing MSH2 expression alone,or missing all 4 MMR proteins.(4).The clinicopathological data of dMMR CRC lacking different MMR proteins was analyzed,finding no obvious differences in the above factors,and the P values were all greater than 0.05.Conclusion:(1).Stage ?-? dMMR CRC is more common in female patients,with a higher incidence on the right side,greater tumor burden at diagnosis,more common T4 stage,higher malignancy,and higher proportion of mucinous adenocarcinoma and younger age of onset.(2).MLH1 and PMS2 co-expression loss is the most common pattern of abnormal MMR protein expression in patients with stage ?-III CRC,followed by concurrent deletions of MSH2 and MSH6,and other types of deletions are rare.(3).There was no significant difference in the clinicopathological data of dMMR CRC with different MMR protein expression deletion. |
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