GENETIC ABNORMALITIES AND MICROSATELLITE INSTABILITY IN COLORECTAL-CANCER

Our purpose was to investigate different genetic abnormalities, such a s K-ras mutations, p53 alterations, and c-myc RNA overexpression, as w ell as microsatellite instability in 63 colorectal tumors obtained fro m patients that had undergone surgery. K-ras point mutations were anal yzed by PCR-RFLP technique, followed by sequencing; p53 protein accumu lation by immunohistochemistry; p53 gene mutations in exons 5-9 were s tudied by the SSCP and sequencing techniques, and c-myc overexpression by Northern blot. Microsatellite instability was performed at chromos omes 2p, 3p, and 11p by a PCR-based technique. Our data indicate a tre nd toward a poorer prognosis in patients who had K-ras transversions; besides, we have obtained a prevalence of c-myc RNA overexpression and p53 exon 7 mutations in the latest stages of tumor progression. In co nclusion, our findings suggest that the recognition of molecular abnor malities might be used in colorectal cancer as a prognostic indicator or to determine the metastatic potential of colorectal adenocarcinomas .