Background: Although tumor stage and grade are important prognostic parameters for patients with renal cell carcinoma, postnephrectomy survival is often difficult to predict. Therefore identifying patients at high risk for disease progression is critical. Using two-color flow cytometry, DNA and proliferation-associated nuclear antigen p105 contents were measured simultaneously in 75 patients with renal cell carcinomas and the ability of these results to predict the survival was assessed.
Methods: Flow cytometric study of the proliferation-associated nuclear antigen p105 was done on cancer cell suspensions from 75 patients with renal cell carcinomas. By setting the cutoff line at the level between the brighter and the dimmer subpopulations in the diploid G0G1 region, the p105-labeling rate was calculated by the p-105DNA dual fluorescence analysis.
Results: The mean p105-labeling rate was 66.8% (median: 67.6%; range: 33.9-93%). The 5-year survival rate of patients with high p105-labeling tumors was significantly lower than that of patients with low labeling tumors (P < 0.05). The following factors were examined univariantly as prognostic factors: Robson's stage, DNA ploidy pattern, grade, and p105-labeling rate. All of these factors except for DNA ploidy pattern were prognostic. The Cox multivariate regression analysis was performed with the three statistically significant variables. Accordingly, these three factors were significantly associated with survival rate and were found to be independent prognostic factors.
Conclusions: The measurement of p105 may provide useful information for predicting prognosis of patients with renal cell carcinoma.