Causes and consequences of microsatellite instability in endometrial carcinoma Journal Article

Authors: Gurin, C. C.; Federici, M. G.; Kang, L.; Boyd, J.
Article Title: Causes and consequences of microsatellite instability in endometrial carcinoma
Abstract: Genetic instability of microsatellite repeat sequences [microsatellite instability (MI)] is commonly seen in tumors associated with the hereditary nonpolyposis colorectal cancer syndrome and is a result of inactivating mutations in any of several genes involved in a particular pathway of DNA mismatch repair. Sporadic (i.e., nonhereditary) manifestations of several tumor types, including colorectal, gastric, and endometrial carcinomas, also exhibit MI in a significant fraction of cases. Many MI+ sporadic colorectal carcinomas are associated with somatic mutations of mismatch repair genes, and several genes with coding region microsatellites are frequently mutated as a result in these cancers. The molecular causes and consequences of MI in sporadic endometrial carcinomas remain obscure, however. The aims of this study were: (a) to identify a series of sporadic endometrial carcinomas with clear evidence of MI; (b) to determine the extent to which somatic alterations in mismatch repair genes are associated with this MI; and (c) to establish whether the genes containing coding region microsatellite repeats that are known to be disrupted in MI+ gastrointestinal cancers are also disrupted in MI+ endometrial carcinomas. Matched pairs of normal and tumor DNA from 57 consecutive cases of endometrial carcinoma were examined for evidence of MI using a consensus panel of microsatellite markers. Fourteen cases (25%) displayed unequivocal evidence of MI, consistent with previously published estimates of the incidence of MI+ sporadic endometrial carcinoma. These cases were subjected to a mutation screen of the coding regions and exon-intron boundaries of the mismatch repair genes MSH2 and MLH1. Although several polymorphisms were detected, no clearly deleterious mutations were found in either of these genes. Notably, however, hypermethylation of the MLH1 promoter region was identified in 10 of 14 (71%) MI+ cases. Somatic mutations in coding region microsatellite repeats in the TGFβIIR, IGFIIR, BAX, E2F4, MSH3, MSH6, BRCA1, and BRCA2 genes were generally rare. Four MI+ tumors (29%) contained somatic mutations in the PTEN gene, only one of which was likely the result of MI. These data indicate that somatic mutational inactivation of known mismatch repair genes does not account for the great majority of sporadic endometrial carcinomas with MI and that a significant fraction of these cases may instead be causally associated with hypermethylation of the MLH1 promoter. Furthermore, genes with coding region microsatellites that are frequently mutated in MI+ gastrointestinal cancers are rarely mutated in MI+ endometrial cancers, implying the existence of alternative molecular targets for the tumorigenic effects of MI in this tumor type.
Keywords: controlled study; human tissue; gene mutation; methylation; promoter region; frameshift mutation; endometrium carcinoma; endometrial neoplasms; colorectal cancer; dna repair; disease association; neoplasm proteins; microsatellite dna; dna methylation; carcinogenesis; nuclear proteins; microsatellite instability; carrier proteins; tumor suppressor proteins; pten phosphohydrolase; gene inactivation; genetic screening; phosphoric monoester hydrolases; microsatellite repeats; promoter regions (genetics); humans; human; female; priority journal; article
Journal Title: Cancer Research
Volume: 59
Issue: 2
ISSN: 0008-5472
Publisher: American Association for Cancer Research  
Date Published: 1999-01-15
Start Page: 462
End Page: 466
Language: English
PUBMED: 9927063
PROVIDER: scopus
Notes: Article -- Export Date: 16 August 2016 -- Source: Scopus
Citation Impact
MSK Authors
  1. Jeffrey Boyd
    112 Boyd
  2. Cheryl Christine Gurin
    6 Gurin
  3. Lan Kang
    7 Kang