[ XXXX and loss of heterozygosity in neoplastic and preneoplastic gastric lesions].

@entity1 @entity4726 @entity124 @entity5 @entity876 @entity74 @entity14 @entity356
BACKGROUND: @entity356 is the leading cause of @entity5 deaths in the general population in Chile, with mortality rates as high as 33.7 per 105 in males in the IX region. A chain of genetic and morphological events precedes the intestinal type of @entity356 . One of them is the called multifocal @entity4726 often associated with intestinal metaplasia. AIM: To study the frequency of @entity124 ( @entity124 ) and loss of heterocigozity (LOH) in neoplastic and preneoplastic lesions of @entity356 , especially intestinal metaplasia. MATERIAL AND METHODS: Ninety four @entity356 biopsies were studied using laser capture microdissection, to obtain well defined cell populations from paraffin-embedded tissues: lymphocytes (control DNA), intestinal metaplasia and @entity356 areas. Primer flanking microsatellite 15 highly polymorphic regions were used to study @entity124 and LOH. Radioactive PCR products were electrophoresed and exposed for autoradiography. RESULTS: LOH was observed in 83% of @entity356 and in 54% areas containing intestinal metaplasia. The most commonly altered regions were the CA repeat associated with the @entity876 gene and the 3p21 region. High grade @entity124 was observed in 11.7% of @entity356 preparations and 17% of intestinal metaplasia associated to @entity5 with @entity124 phenotype. CONCLUSIONS: @entity124 and LOH were frequently observed in intestinal metaplasia glands in @entity1 with @entity356 . The frequency of @entity124 phenotype in gastric @entity1 was slightly lower than the one described in sporadic @entity14 not associated to HNPCC. The high incidence of @entity74 in intestinal metaplasia area, support the idea that intestinal metaplasia is a genetically highly unstable cell population.
