Karyotypic findings in a colonic villous adenoma.

Chromosomes from a patient with a villous adenoma of the colon were examined in detail with fluorescent banding. Of the cells analyzed, 73% had a modal chromosomal number of 48-52. The karyotypic findings show clonal evolution, an additional chromosome #8 being the most frequent abnormality, suggesting that this may be the primary chromosomal change, but other changes such as loss of a Y chromosome and the presence of marker chromosome #1 with duplication of the long arm also were observed. Previous cytogenetic data on large-bowel tumors is summarized. We hypothesize that this chromosomal evidence suggests that tubular adenoma, villous adenoma, and adenocarcinoma may be interrelated steps of a growth disorder.