Objective To investigate influencing factors of deficient mismatch repair(MMR)in colorectal cancer(CRC).Methods A total of 808 patients with CRC treated in the First People's Hospital of Huzhou from October 2019 to March 2023 and Huzhou Central Hospital from July 2020 to September 2022 were selected as the research objects.According to the diagnosis age of CRC patients,under 50 years old patients as early onset CRC group(57 patients),and over 50 years old patients as late onset CRC group(751 patients).Expression of MMR protein in colorectal tissue was detected through immunohistochemical staining.Influencing factor of MMR protein expression deficiency was analyzed.Results Rate of MMR protein deficiency was 6.8%.Univariate analysis showed that compared with proficient MMR patients,deficient MMR patients had significantly lower age,significantly higher proportion of lesions in the right colon,significantly higher Ki67 positive cell rate,significantly longer tumor length,significantly worse differentiation,significantly fewer lymph node metastases,and significantly earlier TNM stage(P<0.05).Logistic regression multivariate analysis showed that age,tumor location,tumor length,and Ki67 positive cell rate were independent influencing factors for the loss of MMR protein expression in colorectal cancer patients(P<0.05).Proportion of MMR defects in early onset CRC group was significantly higher than that in late onset CRC group(P<0.05).Conclusion CRC patients with MMR protein expression deficiency are characterized by younger onset age,more right colon,longer tumor length and higher Ki67 positive cell rate.

Objective:To investigate the efficacy and safety of cold snare polypectomy (CSP) and hot snare polypectomy (HSP) for the removal of colorectal polyps of 10-15 mm.Methods:A total of 173 polyps of 154 patients with at least one polyp of 10-15 mm were resected under colonoscopy from December 2019 to December 2020. Based on Paris classification, the polyps were divided into Ⅰsp, Ⅰs and Ⅱa. According to random number table, the polyps were randomly divided into CSP group ( n=85) and HSP group ( n=88). The polyp size, location, morphology, histological classification, complete resection rate, incidence of complications, resection time and the number of prophylactic clips were compared between the two groups. Results:There were no significant differences in age, sex, indication of colonoscopy or the success rate of intubation at the end of ileum between the two groups. The polyps of the two groups were comparable in size, position, morphology and histological classification. There were no significant differences in the complete resection rate of polyps, rates of intraoperative bleeding and postoperative bleeding or perforation between the CSP group and the HSP group. The operation time in CSP group was significantly shorter than that in HSP group (63.5 ±23.6 s VS 184.3 ±62.4 s, P<0.05). The number of prophylactic clips used in CSP group was significantly less than that in HSP group (0.8±0.5 VS 1.4±0.7, P<0.05). Conclusion:CSP shows similar complete resection rate and complication incidence, and requires shorter operation time and fewer prophylactic clips, compared with HSP, in the resection of colorectal sessile polyps of 10-15 mm.