Clinical-pathological Features And Prognostic Analysis Of MMR-deficient Sporadic Colorectal Cancer

Objective: To study the prognosis and clinical-pathological features of Mismatchrepair (MMR) defect sporadic colorectal cancer (SCRC).Methods: All human colorectal cancer (CRC) samples were collected in Xin HuaHospital Affiliated to Shanghai Jiao Tong University School of Medicine from May2009to May2011. These patients were confirmedly diagnosed as CRC bypathological analysis. The expression level of MMR protein hMLH1and hMSH2inthe CRC tissues was detected by immunohistochemistry. After surgery, the caseswere followed up to collect the survival data. According to the expression of MMRprotein and the clinical-pathological data, we divided all cases into three groups:1)MMR-deficient SCRC,2) MMR-proficient SCRC,3) hereditary non-polyposiscolorectal cancer (HNPCC). Methods such as chi-square testing, means±standarddeviation, t testing and Kaplan–Meier estimator were used to analyze the data. Theresult is statistically significant when it appears to be P<0.05.Results:1. There is a statistically significant difference between MMR-deficient SCRC andMMR-proficient SCRC in tumor sites and tumor malignant degree (P<0.05) butnot in average onset age, tumor stage, lymph node metastasis, the gender orthree-year overall survival (P>0.05).2. There is a statistically significant difference between MMR-deficient SCRC andHNPCC in average onset age and lymph node metastasis (P<0.05) but not intumor sites, tumor stage, tumor malignant degree, the gender or three-yearoverall survival (P>0.05).Conclusions:1. The sign of MMR deficiency can be found in some cases of SCRC patients.Mutated hMLH1is the most common one among variable mutation types.2. The clinical-pathological features of MMR-deficient SCRC are quite unique inaverage onset age, tumor sites, tumor malignant degree and lymph node metastasis. A deeper study should be helpful to classify the CRC types in theaspect of both clinical pathology and prognosis analysis.3. The three-year overall survival rate of MMR-deficient SCRC patients is betweenMMR-proficient SCRC and HNPCC patients. Our study is yet to find anysignificant difference among MMR-deficient SCRC and two other groups inthree-year overall survival rate.