DINUCLEOTIDE REPEAT POLYMORPHISMS AT 9 LOCI IN SPORADIC COLORECTAL-CANCER

Genomic instability in the form of microsatellite alterations at nine loci on chromosomes 2p, 8p, 10p, 11p, and nm23-H1 locus on 17q21.3 wer e studied in sporadic colorectal tumors. Alterations in dinucleotide r epeats in tumor DNA as larger allele, smaller allele, or loss of heter ozygosity (LOH) were observed, Forty percent of tumor showed an RER(+) phenotype. A significantly high number of alterations was detected at loci of chromosome 8p. The markers on chromosomes 2p, 10p, and lip di d not show such significant alteration. LOH was found to be associated with the nm23-H1 locus. No correlation was found between the age, sit e of tumor occurrence, or metastasis and the microsatellite instabilit y.