THYMIDINE LABELING INDEX IN COLORECTAL-CARCINOMA - RELATION TO CLINICOPATHOLOGICAL PARAMETERS AND TO MITOTIC INDEX

Two cell-kinetic parameters, the thymidine labeling index (T-LI) and t he mitotic index (MI) were determined for a prospective series of 74 p rimary colorectal cancers. Dukes' stages were used to define the exten t of the tumor: 10 tumors were classified as Dukes' A, 36 as Dukes' B, and 22 as Dukes' C. Of these tumors, 14 were well-differentiated, 44 moderately differentiated, and 15 poorly differentiated adenocarcinoma s. The H3dT-LI values obtained varied widely, from 2.5 to 38.9% (media n value: 16.8%). The MI shows a range of from 0 to 13.2% with a median value of 3.2%. The T-LI values were independent of the sex and age of the patients and of the histological grading and Dukes' stage. Conver sely, the MI was related to histological grading. This study indicates that the T-LI, whose application has reached the gold standard, still represents an independent parameter and the most sensible, objective, and specific complementary method for the analysis of the S phase.