Chromosomal banding patterns in human large bowel adenomas.

Chromosome studies were performed on direct preparations of 38 benign human large bowel adenomas by fluorescent banding techniques. Five adenomas had a normal diploid karyotype line. Six adenomas had numerical abnormalities, and seven polypoid lesions exhibited structural and numerical changes. In 20 adenomas without analyzable metaphases, it was presumed that the cells were dividing at a lower rate. Mosaics were observed in 25% of cases. The most common finding was trisomy of 7, 8, or 13.