The aim of this study was to evaluate the prognostic information of soluble carbonic anhydrase (CA) IX expression in renal cell carcinoma (RCC).
Patients and methods: Serum CA IX was analysed in 361 patients. Tumour type, TNM stage, nuclear grade, and RCC-specific survival were assessed. Serum and immunohistochemical expression were compared.
Results: Median serum CA IX expression was 141 (range 2-4, 181) pg/ml. Levels were significantly higher in 287 patients with clear cell, compared to 40 papillary (p<0.001) and 22 oncocytoma (p=0.002), but not to 12 chromophobe RCC (p=0.35). Serum CA IX in clear cell RCC was positively correlated to TNM stage (p=0.002). There was a positive trend between serum and immunohistochemical CA IX expression. In a multivariate analysis of clear cell RCC, TNM stage and nuclear grade were independent prognostic factors.
Conclusion: Serum CA IX was higher in clear cell RCC compared to other RCC types. In clear cell RCC, serum CA IX correlated to TNM stage, but not survival.