title: K-ras mutations in endometrial carcinomas with microsatellite instability.
abstract: K-ras mutations are known to occur in hyperplasias and carcinomas of the endometrium. No clear correlation has been found yet between K-ras mutations and microsatellite instability (MI) in these lesions. Fifty-eight endometrial carcinomas (ECs) and 22 endometrial hyperplasias (EHs) were analysed for K-ras mutation by single-strand conformational polymorphism analysis (SSCP), restriction analysis, and DNA sequencing. MI status had been established previously at five dinucleotide loci and was reconfirmed with markers BAT-25 and BAT-26 by SSCP. K-ras mutations were detected in 11 ECs (18.9%). All 11 tumours were endometrioid carcinomas. K-ras mutations were more frequent in MI-positive (6/14, 42.8%) than in MI-negative tumours (5/44, 11.3%) (p=0.017). Methylation-related transitions were detected in five of the six MI-positive tumours but in only one of the five MI-negative carcinomas. K-ras mutation was identified in only one atypical EH (1/22, 4.5%); in this case, the EH co-existed with EC and both lesions exhibited MI. The results support a close relationship between K-ras mutations and the phenomenon of MI in endometrial carcinomas. The frequent occurrence of methylation-related transitions in these tumours may indicate a cause-effect relationship with the altered methylation status which has been described in association with MI.
authors.affiliation: Department of Pathology, Hospital Santa Creu i Sant Pau, Autonomous University of Barcelona, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Lagarda
authors.forename: L
authors.initials: L
authors.lastname: Catasus
authors.forename: R
authors.initials: R
authors.lastname: Arguelles
authors.forename: X
authors.initials: X
authors.lastname: Matias-Guiu
authors.forename: J
authors.initials: J
authors.lastname: Prat
mesh_terms: D002277:Carcinoma / Q000235:genetics*; D019175:DNA Methylation; D004714:Endometrial Hyperplasia / Q000235:genetics; D016889:Endometrial Neoplasms / Q000235:genetics*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA