Pathologic stage is the main prognostic factor for predicting outcome in renal cell carcinoma (RCC). Because of its unreliability in predicting tumor progression, other factors are needed to provide additional prognostic information.
The expression of CD44, cyclooxygenase 2, and platelet-derived growth factor receptor alpha (PDGFR-alpha) was evaluated as a potential prognostic factor for survival in patients with RCC.
Sixty-two patients (42 men and 20 women; median age, 61 years), undergoing partial (10 cases) or radical (55 cases) nephrectomy for RCC were retrospectively analyzed by immunohistochemical analysis for CD44, cyclooxygenase 2, and PDGFR-alpha expression. Impact of various factors on disease-specific and overall survival was calculated using Cox proportional hazards models.
There was a gradual increase in CD44 and cyclooxygenase 2 expression with increasing RCC nuclear grade. In contrast, PDGFR-alpha expression showed no consistent relationship with nuclear grade. On univariate analysis, metastasis at time of surgery (P < .001), tumor size (P = .004), pathologic stage group (P = .001), and nuclear grade (P = .004) were correlated with disease-specific survival. On multivariate analysis, only the presence of metastasis at diagnosis (P < .001) was significant. For overall survival, metastasis (P < .001), tumor size (P = .02), pathologic stage group (P = .01), nuclear grade (P = .003), and PDGFR-alpha (P = .03) were significant on univariate analysis. Only metastasis (P = .001) and PDGFR-alpha (P = .03) were significant on multivariate analysis.
When combined with other variables, PDGFR-alpha expression in RCC may provide additional predictive value related to the patient's overall survival. However, CD44 and cyclooxygenase 2 do not seem to be independent prognostic indicators in predicting outcomes for patients with RCC.