Chromosome 18 allele loss at the D18S6 locus in human colorectal carcinomas.

This is the first report of chromosome 18 allele loss in colorectal carcinomas from FAP patients and concurrent allele losses on chromosomes 5 and 18 in sporadic colorectal cancer. This is based on our investigation of twenty-two colorectal carcinomas from sporadic cases and FAP patients which revealed tumor-specific allele loss of at least 44% at the D18S6 locus on chromosome 18 in informative cases. These results coupled with the tentative assignment of an HNPCC gene to chromosome 18 suggests that a gene on chromosome 18 may be involved in the etiology of some colon cancers. Possible mechanisms involving genetic changes on chromosome 18 in colon cancer are discussed in relation to tumor- or growth-suppressor genes.