Soluble ectodomain of c-erbB-2 oncoprotein in relation to tumour stage and grade in human renal cell carcinoma.

The soluble ectodomain of c-erbB-2 oncoprotein was measured using a sandwich enzyme immunoassay in sera from 184 patients with renal cell carcinoma before initiation of treatment. The median serum level was 2062 U ml(-1) (range 865-4905 U ml(-1)). Levels were unaffected by sex, age and renal function. An inverse relation between disease stage (P = 0.0017) and tumour grade (P = 0.0009) and the serum level of c-erbB-2 ectodomain was observed. Survival time for patients with serum levels above median level was significantly longer than for patients with lower levels (P = 0.003). In a multivariate analysis, c-erbB-2 oncoprotein lost its prognostic information, while tumour stage and tumour grade were identified as independent prognostic factors.