Serum immunosuppressive acidic protein as a potent prognostic factor for patients with metastatic renal cell carcinoma

Background: Estimation of survival probability of individual patients with metastatic renal cell carcinoma was difficult owing to diverse prognostic f actors. We analyzed serum immunosuppressive acidic protein (IAP) levels and the cutoff value, then tested its validity for assessing patients' prognos es. Methods: Serum IAP was measured longitudinally in 84 patients with metastat ic disease. Before therapy, cutoff levels of IAP were tested every 20 mug/m l between 600 and 1200 mug/ml. The prognostic importance of IAP and its cut off level was estimated. Results: The cutoff level of IAP was set at 800 mug/ml for 40 patients who had metastatic disease with the primary tumor in situ and for 44 patients w ith recurrent disease. IAP was found to be a significant prognostic factor for both patient groups. Conclusions: Serum IAP is an important prognostic factor for patients with metastatic renal cell carcinoma. Stratification of patients according to pr ognosis is feasible using the cutoff level.