Loss of Apc+ in intestinal adenomas from Min mice.

Allelic loss at the Apc locus in spontaneously occurring intestinal adenomas from mice heterozygous for the ApcMin nonsense mutation was analyzed using a site-specific quantitative polymerase chain reaction assay. All 97 of the intestinal adenomas analyzed showed extensive loss of the wild-type Apc (Apc+) allele. Quantitative polymerase chain reaction analysis of loci linked to Apc indicated loss of the chromosome carrying Apc+. Only one copy of the homologue carrying ApcMin remained in the intestinal adenomas. Possible reasons for the difference in the mechanism of Apc+ loss between human and Min mouse intestinal adenomas are discussed.