title: Loss of hMSH2 and hMSH6 expression is frequent in sporadic endometrial carcinomas with microsatellite instability: a population-based study.
abstract: Microsatellite instability (MSI) seems to be important in the development of various human cancers including sporadic endometrial cancer. It has previously been shown that alterations in the mismatch repair gene hMLH1 seem to be important for the development of MSI in these tumors. The role of the other mismatch repair genes hMSH2 and hMSH6 has been less well studied, but investigations on patients with hereditary nonpolyposis colorectal cancer indicate that these genes also may be involved. We therefore wanted to investigate the pattern of hMSH2 and hMSH6 expression in a prospective and population-based series of endometrial carcinomas with known hMLH1 expression and MSI status. A total of 138 patients were studied, and pathological staining was seen in 19 cases (14%) for hMLH1, 26 cases (19%) for hMSH2, and 17 cases (12.3%) for hMSH6. Pathological hMLH1 expression was more frequent among tumors with high MSI (those positive for four to five of five markers), whereas pathological expression of hMSH2 and hMSH6 was more frequent among tumors with intermediate MSI (those positive for two to three of five markers). MSI was significantly correlated with pathological expression of hMLH1 (P < 0.001), hMSH2 (P = 0.04), and hMSH6 (P = 0.001). In the group with high MSI, 14 of 16 tumors (88%) showed pathological expression for at least one of the markers. The expression of hMLH1, hMSH2, or hMSH6 did not significantly influence survival. In conclusion, pathological expression of hMLH1 does not seem to account for all tumors with a MSI-positive phenotype in this population-based series of endometrial carcinomas. Our data indicate that the other mismatch repair genes hMSH2 and hMSH6 are also involved, especially in cases with intermediate MSI.
authors.affiliation: Department of Pathology, The Gade Institute, Bergen, Norway.
authors.forename: Ingunn
authors.initials: I
authors.lastname: Stefansson
authors.forename: Lars A
authors.initials: LA
authors.lastname: Akslen
authors.forename: Nicola
authors.initials: N
authors.lastname: MacDonald
authors.forename: Andy
authors.initials: A
authors.lastname: Ryan
authors.forename: Soma
authors.initials: S
authors.lastname: Das
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Jacobs
authors.forename: Helga B
authors.initials: HB
authors.lastname: Salvesen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D020137:Base Pair Mismatch; D002352:Carrier Proteins; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D016889:Endometrial Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D018895:Microsatellite Repeats / Q000235:genetics; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011401:Promoter Regions, Genetic; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D015996:Survival Rate
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein