Epithelial cell kinetics in the crypts of familial polyposis of colon

Epithelial cell kinetics were examined in the uninvolved part of the rectal mucosa in nine cases of familial polyposis of colon, six cases of their first degree relatives, and six control cases. The biopsied specimen were incubated for two hours in the culture medium containing H3-thymidine. In the control cases, the proliferating zone was confined to the lower two thirds of the crypt in all except one case. Six of the nine cases of familial polyposis of colon had crypts with altered proliferating zone, i.e., incorporation of H3-thymidine was observed in the upper one third of the crypt as in the case of adenomatous polyps. Three of the six cases of the first degree relatives showed such change. There were significant differences in the incidence of such change between controls and familial polyposis of colon or their first degree relatives, whereas no significant differences between familial polyposis of colon and their first degree relatives.