Carbonic anhydrase IX is an independent predictor of survival in advanced renal clear cell carcinoma: implications for prognosis and therapy.

Metastatic renal cell carcinoma (RCC) has a poor prognosis and an unpredictable course. To date, there are no molecular markers which can reliably predict RCC outcome. We investigated whether a novel kidney cancer marker, carbonic anhydrase IX (CAIX), is associated with progression and survival.Immunohistochemical analysis using a CAIX monoclonal antibody was performed on tissue microarrays constructed from paraffin-embedded specimens from patients (N = 321) treated by nephrectomy for clear cell RCC. CAIX staining was correlated with response to treatment, clinical factors, pathologic features, and survival.CAIX staining was present in 94% of clear cell RCCs. Survival tree analysis determined that a cutoff of 85% CAIX staining provided the most accurate prediction of survival. Low CAIX (