Flow cytometry of biopsy specimens from ulcerative colitis, colorectal adenomas, and carcinomas.

The cellular DNA distribution pattern in biopsy specimens from all main segments and neoplastic lesions of the large bowel, obtained from 16 patients with ulcerative colitis, 22 with adenomas, 17 with carcinoma, and 20 controls, has been studied by the flow cytometry technique. Aneuploid cell populations were demonstrated in three patients with ulcerative colitis (19%), in six with tubular adenomas (27%), and in nine with carcinoma (53%). Aneuploid cells were found in all cases of poorly differentiated adenocarcinomas. The fractional number of cells with a DNA content corresponding to the DNA synthetic and G2M phases of the cell cycle was defined as the 'proliferative index' (PI). In controls PI and its complementary G1 cell fraction varied significantly (p less than 0.005) between the segments, on the basis of analysis of variance. When compared two by two, PI was significantly higher in the sigmoid colon (p less than 0.01) and rectum (p less than 0.05) than in the ascending part. The PI of uninvolved mucosa from adenoma patients with diploid histograms was significantly higher than that in controls (p less than 0.01), ulcerative colitis (p less than 0.05), and cancer patients (p less than 0.05), when dependence on segment was taken into account.