A Study On Expression Of Mismatch Repair Gene,Microsatellite Instability In The Peutz-Jeghers Polyps

Background and Objection:Peutz-Jeghers syndrome(PJS)is a rare autosomal dominant hereditary disease characterized by gastrointestinal hamartomatous polyps and mucocutaneous melanin deposition,the incidence rate is 1/200 000.Multiple polyps in the gastrointestinal tract in patients with adolescent often cause intussusception,intestinal obstruction,gastrointestinal bleeding.The PJS patients with digestive tract polyps have malignant potential and is associated with the benign or malignant tumor of reproductive system and many other organs.The PJS family of the cancer disease incidence rate also higher than the general population.At present,there is no intervention measures to cure and prevent PJS occurrence and pathogenesis of malignant polyps.Therefore,it is of very important significance to explore approach and mechanism of PJS related canceration.PJSis a cancer predisposition syndrome,foreign research shows that,the PJS patients has a high incidence of 19%-32%of malignant tumors,average age is young(42-45 years).Dominated by gastrointestinal tumors(51-69%),secondly for gynecological tumor and breast cancer 22-26%.The pathogenesis of PJS gastrointestinal cancer has been controversial.Gastrointestinal tract malignant tumor in the end by hamartoma,adenoma and normal mucosa was present(de nove)and?There is no exact conclusion.Some studies have found that PJS occurrence of gastrointestinal malignant tumor location is not always with the hamartomatous polyp location is consistent.However,since 1965 a case "by the progress of duodenal hamartoma of the twelve refers to cancer"reports began,at home and abroad have a lot of patients with PJs polyp of gastrointestinal tract "hamartoma adenoma carcinoma" pathological process reported.On the basis of this theory,scholars have suggested that endoscopic polypectomy in order to reduce the risk of malignant tumor.According to the etiology of colorectal cancer,divided into genetic and non genetic two.Which caused by the genetic factors of colorectal cancer with Lynch syndrome(Lynch Syndrome,LS)and familial adenomatous polyposis colorectal cancer(familial adenomatous,polyposis,FAP)and some sporadic colorectal cancer.Domestic and foreign studies have found that the occurrence and development of LS,FAP and sporadic colorectal cancer have different molecular biological pathways,which are mainly divided into two types:chromosome instability and microsatellite instability.FAP and 85%of sporadic colorectal cancer occurred mainly caused by chromosomal instability,and in is of 90%and 10%of sporadic colorectal cancer occurrence process,mainly microsatellite instability(MSI)play a decisive role.Defects in mismatch repair genes(repair mismatch,MMR)lead to microsatellite instability in tumors.Microsatellite instability(MSI)detection method is divided into two types:mismatch repair gene immunohistochemistry method and gene mutation detection method.HMLH1,hMSH2,hPMS2,hMSH6 four genes were detected by immunohistochemical technique to determine the MSI method,which has been widely used at home and abroad.Gene mutation detection by the number of microsatellite loci to detect MSI,selection of loci basically follows the 1997 microsatellite instability and replication error phenotype in tumor detection and familial cancer prediction research on the application of "recommended microsatellite loci,different researchers or institutions increased detection of other sites on the basis of this,in order to improve the specificity and sensitivity of detection results.LS's disease is most commonly reported in MLH1,MSH2,MSH6,and PMS2,because of mutations in the MMR gene.MMR gene defects lead to the loss of the normal allele mismatch repair ability of tumor,and then cause tumor microsatellite instability.A MMR mutation carrier has a high risk of colorectal cancer(25-70%)and endometrial cancer(30-70%)as well as other tumors.PJS as a cancer susceptibility disease,the cause of its occurrence is not completely clear.Research suggests that the oncogenic mutations occurred in the pathogenic gene LKB1/STK11.However,Nicholas in so far the largest review clinical research(419 patients with PJs)found,LKB1/STK11 mutation with PJs carcinogenesis occurs,there is no correlation between rate,Hamid for 46 PJs families suffering from cancer mechanism research also confirmed the this view.These studies suggest that there are other unknown factors(signaling pathways or genes)that are involved in the process of PJS evolution.Due to the MMR in mismatch repair genes and functional changes and the emergence of MSI in patients with PJs patients have many similar phenotypes:tumor susceptibility,genetic,high incidence of rectal cancer,age of cancer is low,and the prognosis is relatively good,and about PJs in mismatch repair gene expression and microsatellite instability in qualitative research,the literature has not been reported.Thus we have carried out the study on the gene expression of PJS and MSI in the repair of the mismatch repair.The aim of the study was to explore the role of mismatch repair genes hMLH1,hPMS2,hMSH2,hMSH6 and MSI in the occurrence and development of PJS,and to provide help for the further study of PJS.Methods:1,collecting 36 cases of fresh PJs polyps,20 cases of fresh colorectal adenoma tissues,20 cases of fresh colorectal adenocarcinoma,respectively RNA extraction and wax block production,as compared with 20 fresh cases of normal colon mucosa,through the location and severity of RT-PCR and immunohistochemical method to detect hMLH1,hPMS2,hMSH2,hMSH6 gene expression.2,collected on behalf of the PJ polyps evolution process in different stages of tissue samples:20 cases of normal colorectal mucosa,25 hamartomatous PJ polyps,11 cases of adenoma like variable PJ polyps and 1 gold focal cancerous PJ polyps;by immunohistochemical method in specimens of PJ detection location and degree of wrong mismatch repair gene hMLHl,hPMS2,hMSH2,hMSH6 protein expression.3,of 25 hamartomatous PJ polyps,11 cases of adenoma like PJ polyps,1 gold focal cancerous PJ polyp specimens extracted DNA organization and to correspond to the patient's blood as normal tissue as control.The NR21,Bat26,PentaC,NR27,Bat25,PentaD,,Amel,,NR24 and Mono27 were detected on the 3730x1 ABI genetic analyzer.4,statistical methods:SPSS13.0 statistical software for statistical processing,data for the measurement data,using multiple sets of one-way analysis of variance(Way ANOVA One).U Test Mann-Whitney method was used to compare the two two groups.Count data using chi square test-differential expression of RxC table.If the data does not conform to the normal distribution or the multi class data,the rank sum test method(H Kruskal.Wallis)is adopted.Correlation analysis of the expression level of hMLHl,hPMS2,hMSH2,hMSH6,using partial correlation analysis method.R partial correlation coefficient indicates the degree of correlation between the three of the two two.With bilateral a=0.05 as the test level,the test standard to P<0.05 as a significant difference or have a correlation.Results:1,in normal colorectal mucosa as control,in PJs polyps,colorectal adenoma,colorectal adenocarcinoma,hMLH1,hPMS2 in PJs group mRNA and protein expression was significantly lower than that of adenocarcinoma and adenoma group.There was no significant difference between the two groups after.There was no significant difference in the expression of hMSH2 and hMSH6 in the three groups.2,in the hamartomatous PJ polyp,adenomatous change PJ polyps and focal cancerous PJ polyp detection of four kinds of mismatch repair gene expression showed that hMLH1,hPMS2,hMSH2,hMSH6 expression level with the evolution process of PJ polyp canceration weakened gradually.In normal colorectal mucosa expression showed strong positive frequency expression,in hamartomatous PJ polyps expression began to weaken,and with normal mucosa hamartoma tumor PJ polyp adenoma:a variable evolution of PJ polyp in a colorectal cancer,and the expression gradually decreased.The expression of hMLHl and hPMS2 protein expression was missing in the malignant transformation of PJ polyps.3,The detection of microsatellite instability in 3,25,11 PJ hamartomatous polyps were adenomatous polyps,1 PJ focal cancerous polyps and 20 cases of PJ paraffin specimens of colorectal adenocarcinoma specimens in NR21,Bat26,PentaC,NR27,Bat25,PentaD,Amel,NR24,Mono27 nine sites PJ:hamartomatous polyp group in 23 cases(92%)showed microsatellite instability(MSS),2 cases(8%)showed low microsatellite instability(MSI-L);adenomatous polyp group PJ degeneration in 7 cases(63.6%)showed microsatellite instability(MSS),3 cases(27.3%)microsatellite instability was low(MSI-L),1 cases(9.1%)showed MSI-H(MSI-H);1 PJ focal cancerous polyps showed MSI-H(MSI-H).Conclusions:1,The expression of hMLHl,mRNA hPMS2 and protein was significantly lower than that in colorectal adenoma and colorectal adenocarcinoma tissue,and the difference was significant between and PJS,while there was no significant difference in the expression of adenocarcinoma and adenoma.There was no significant difference in the expression of hMSH2 and hMSH6 in the three groups.2,hMLH1,hPMS2,hMSH2,hMSH6 expression with the evolution process of the PJ polyp canceration decreased gradually,suggesting the PJ polyp formation may early involvement PJ canceration of polyps and polyps will continue to progress in the process of the important factor in the control of.3,degree of micro satellite instability with the evolution process of the PJ polyp canceration increased gradually,its in the hamartoma polyps in 92%as microsatellite stable(MSS),and in adenomatous change PJ polyps and focal cancerous polyps PJ 36.4%showed microsatellite instability type(MSI),micro microsatellite instability degree increased with the degree of malignancy increased and increased.4,wrong mismatch repair gene hMLH1,hPMS2 and PJs polyps malignant transformation,microsatellite instability with PJs polyp canceration degree increases,and mismatch repair gene detection with consistency.Mismatch repair gene,MSI may play a role in the process of malignant polyps in PJS.MMR function changes and microsatellite instability may occur in colorectal cancer patients with PJS.