Cell proliferation in renal cell carcinoma--a comparative study of cell kinetic methods

Four different methods of assessing cell proliferation in renal cell carcinoma were compared in a total of 136 samples to analyze their degree of agreement and usefulness. The methods compared were flow cytometric S-phase (S-FCM) analysis, proliferating cell nuclear antigen expression detected by immunohistochemistry (PCNA-IHC), in vivo iododeoxyuridine incorporation analyzed with immunohistochemistry (IdUrd-IHC), and flow cytometry (IdUrd-FCM). The mean S-FCM fraction was 5.9%, compared with a mean PCNA-IHC labeling index of 4.7%. The mean labeling indices obtained by IdUrd-IHC and IdUrd-FCM were 1.2% and 1.7%, respectively. The four methods correlated well with each other. When the methods were compared according to Bland and Altman, good agreement was shown. A statistically significant difference in proliferation between diploid and aneuploid tumor samples was found with all methods (P < 0.001). The results showed that the four different methods provided comparable information on proliferative activity, although different cell cycle compartments were monitored.