[Significance of plasma interleukin-6 in the diagnosis of renal cell carcinoma].

The significance of interleukin-6 (IL-6) in the diagnosis of renal cell carcinoma (RCC) was investigated. In RCC patients, we found that, even when IL-6 was produced by RCC, the plasma level of IL-6 was under the limit of detection in almost all patients with a classification of T2N0M0 or lower. In the case of rapidly progressive type of bulky metastasis, the concentration of IL-6 in plasma was high, but the IL-6 level correlated well with the serum C-reactive protein (CRP) level. These findings suggest that IL-6 has little potential to serve as a new tumor marker for RCC.