Comparison between different cell kinetic variables in human breast cancer

Cell kinetics holds a prominent role among biological factors in predicting clinical outcome and response to treatment in neoplastic patients. Differe nt cell kinetic variables are often considered as valid alternatives to eac h other, but the limited size of case series analysed in several studies an d the lack of simultaneous determinations of all the variables on the same tumours do not justify this conclusion. In the present study, the correlati on between [H-3]thymidine labelling index ([H-3]dT LI), flow cytometric S p hase cell fraction (FCM-S) and Ki-67 immunoreactivity (Ki-67/MIB-1) was ver ified and the type of correlation with the most important clinical, patholo gical and biological patient and tumour characteristics was investigated in a very large series of breast cancer patients. Ki-67/MIB-1, FCM-S and [H-3 ]dT LI were determined in 609, 526 and 485 patients, respectively, and all three cell proliferation indices were evaluated in parallel on the same tum our in a series of 330 breast cancer patients. All the cell kinetic determi nations were performed within the context of National Quality Control Progr ammes. Very poor correlation coefficients (ranging from 0.37 to 0.18) were observed between the different cell kinetic variables determined in paralle l on the same series of breast cancers. Moreover, Ki-67/MIB-1 and FCM-S sho wed a significant relationship with histological type, grade and tumour siz e, whereas statistically significant correlations were not observed for [H- 3]dT LI. In conclusion, the results show that the different cell kinetic va riables provide different biological information and cannot be considered a s alternatives to each other.