Proliferative activity in normal colon mucosa and tumor tissue: clinical implications

The study deals with the analysis of proliferative activity in colon carcinomas and adjacent normal appearing mucosa, evaluated with in vitro 3H-Thymidine and autoradiography. In the colonic mucosa no significant differences in 3H-Thymidine Labelling Index (TLI) were observed in relation to the distance of the sample from the neoplasia. The distribution of S-phase cells along the crypt length is low at the bottom, increases rapidly with a maximum within the lower 25% and decreases in the highest positions. When the proliferative activity is increased there is the possibility of expanding the proliferative compartment towards the luminal region of the crypt. The division of the crypt into 5 parts makes it possible to identify 2 different patterns: the first with a very high TLI in the lower fifth, then a sharp decrease and without labelled cells in the highest parts; the second with labelled cells present also in the luminal fifth. These 2 aspects are characteristic of specimens with the lowest and the highest TLI values respectively. The analysis of TLI in colo-rectal cancers shows that cell kinetics parameters are not related to clinical and histopathological features such as sex, age, Dukes and TNM stages and grade of differentiation.