interleukin-6 ( il-6 ) was found to be a growth factor of renal cell carcinomas furthermore , renal cell carcinomas freshly isolated from the patients expressed mrna of il-6 and secreted biologically active il-6 under the culture conditions where the tumor cells could grow , but they did not produce il-6 nor proliferate in the absence of fetal calf serum .
C0022646
renal
C0007134
renal cell carcinomas