Study On Relationship Between Expression Of Survivin And Methylation Of HMLH1 Gene Promoter In Colorectal Cancer

Objective: Study the expression of survivin protein in colorectal cancer,the methylation of h MLH1 gene promoter,and the relationship between the two elements and the occurrence,development and prognosis of colorectal cancer.Materials and Methods: Select 45 patients with colorectal cancer who underwent adical surgery(the pathological diagnosis was clear and the margin was negative.The patients were not treated with any anti tumor therapy before operation),and were followed up for 5 years.Control group: 25 cases was selected from a tumor 5 cm above the normal mucosa(postoperative pathological diagnosis was clear).Find specimens of paraffin blocks corresponding to a patient and fresh frozen tissuerespectively in the pathology department and tissue bank of the first Hospital of Jilin University.According to the age,sex,tumor location,T stage,differentiation degree,lymph node metastasis,vascular invasion and other related basic clinical datas,all the cases were devided in groups.The expression of survivin protein and the methylation of h MLH1 gene promoter were detected by immunohistochemical method(IHC)and methylation specific PCR(MSP).Results were input into SPSS 22.0 statistical software.Results: 1.The positive expression rate of survivin protein in colorectal cancer was 64.44%(29/45),significantly higher than 8.89%(4/45),the positive rate of expression in normal colorectal.The difference was significant(P<0.001).It was correlated with T stage,differentiation and lymph node metastasis(P<0.05),but not the patients' age,gender,tumor location and vascular invasion(P>0.05).1.The methylation rate of h MLH1 gene promoter in colorectal cancer was 35.56%(16/45),but methylation was not found in normal colorectal tissues.The difference was significant(P<0.001).It was correlated with tumor differentiation(P=0.001),but not the patients' age,gender,tumor location,T stage,lymph node metastasis and vascular invasion(P>0.05).3.The expression of survivin protein and the methylation of h MLH1 gene promoter were positive correlation in colorectal cancer(r=0.358,p=0.016).4.In colorectal cancer,the postoperative survival rates of survivin protein positive group and negative group,were 27.53% and 65.45%.The survival situations of survivin negative patients were better than those of the patients with positive(P=0.006).5.In colorectal cancer,the postoperative survival rates of h MLH1 gene promoter methylated and unmethylated patients,were was 25% and 50.78%.The survival situations of the unmethylated patients were significantly better than the methylated patients(P=0.037).Conclusion: 1.The expression of survivin protein in colorectal cancer tissue was significantly higher than that in normal colorectal tissue,and correlated with T stage,differentiation degree and lymph node metastasis.2.The methylation of h MLH1 gene promoter in colorectal cancer tissue was significantly higher than that in normal colorectal tissue,and correlated with the degree of tumor differentiation.3.The expression of survivin protein and the methylation of h MLH1 gene promoter were positive correlation in colorectal cancer.4.The expression of survivin protein and methylation of h MLH1 gene promoter were all correlated with poor prognosis in colorectal cancer.