Autoradiographic and flow cytometric assessment of cell proliferation in primary colorectal cancer: relationship to DNA ploidy and clinicopathologic features.

Two cell-kinetic parameters, the [3H]thymidine-labeling index [3H]dT LI and the flow-cytometric S-phase cell fraction (FCM-S), and DNA ploidy were determined for a prospective series of 110 primary colorectal cancers. Aneuploidy was observed in 66% of tumors and more than one aneuploid peak was present in 12%. The frequency of aneuploid tumors was higher in rectal (80%) and left-colon (70%) cancers than in right-colon cancers (51%), and multiple aneuploid clones were detected more frequently in men than in women (p = 0.03) and more frequently in advanced Dukes' D-stage patients (p = 0.08). The median [3H]dT LI value (17.4%) was similar to the FCM-S value determined by a planimetric model (16.2%) and somewhat higher than the FMC-S value obtained by an optimization procedure (11.2%). However, there was no significant relationship between the [3H]dT LI value and either FCM-S value for individual tumors. Moreover, FCM-S values were higher in aneuploid than in diploid tumors, whereas [3H]dT LI values were independent of DNA-ploidy status; [3H]dT LI and FCM-S were also related differently to some clinical and pathological features such as tumor site and histology. These findings suggest different biological meanings for these 2 cell-kinetic parameters, which should not be used interchangeably.