[Elaboration of erythropoietin in cultured cells]

Patients with renal cell carcinoma (RCC) rarely develop erythrocytosis. Mechanism of this phenomenon has been disclosed by a series of recent studies using tissue culture technology that erythropoietin (Ep) elaborated by tumor cells. In this review article, the results of in vivo and in vitro studies using the established cell line KU-2 a nude mouse transplantable strain originated from a patient, T.N., with an Ep producing RCC showing erythrocytosis are introduced and discussed on the mechanism of Ep production by the cultured cells. The cultured RCC cells are eligible to produce Ep at stage of over confluence forming the "domes" which are conceivable as the differentiation of the RCC cells in vitro.