PREVALENCE OF PARANEOPLASTIC ERYTHROPOIETIN PRODUCTION BY RENAL-CELL CARCINOMAS

The prevalence of increased serum immunoreactive erythropoietin (Epo) was determined in a prospective study of 49 patients with renal cell c arcinoma. Measured by a monoclonal antibody based commercial enzyme-li nked immunoassay, the Epo concentration was above the normal range, de termined in nonanemic humans, in four of the renal carcinoma patients. Since three of these were anemic, their increased Epo level was consi dered to be appropriate. The high estimate of serum Epo (218 U/l) in t he fourth patient, who was not anemic, was not confirmed when tested b y radioimmunoassay. Thus, in contrast with earlier studies, our result s indicate that increased Epo is not a clear serological renal cell ca rcinoma marker. In addition, when monolayer cell cultures of 14 differ ent established human renal carcinoma lines were screened, none of the se released immunoreactive Epo in measurable amounts.