Cell cycle parameters in human colon. Comparison between primary and recurrent adenocarcinomas, benign polyps and adjacent unaffected mucosa

The duration of S phase and the labeling index were measured in adenocarcinomas, in polyps and in adjacent unaffected mucosa of a same patient. The in vitro double labeling technique was employed. The S phase duration in tumors was significantly longer than in unaffected mucosa and polyps. This agrees with previously reported data on human skin,16 colon and rectum2 and supports the suggestion that a long S phase might correlated with carcinogenesis. The labeling index in the mucosa adjacent to the tumors is higher than previously measured in normal tissue. Following colectomy however, the labeling index in unaffected mucosa and tumor was lower than prior to surgery. This suggests the disappearance of a systemic factor (in the colon?) which positively regulates the proliferative activity in the rectal and colonic musoca. The maintainance of a lengthened S phase duration in the recurrent tumor where L.I. is lowered, indicates that the proliferation rate and the S phase duration are regulated by separate control factors.