Production of erythropoietin and multiple cytokines by metanephric adenoma results in erythrocytosis.

This is the first report of direct evidence that metanephric adenoma cells produce erythropoietin and other types of cytokines, which may be the cause of the high incidence of erythrocytosis in patients with this tumor. The purpose of the study was to establish a metanephric adenoma cell line in vitro from nephrectomized tumor tissue in order to investigate the ability of metanephric adenoma cells to produce erythropoietin and other types of cytokines. The tumor tissue was obtained from a 16-year-old boy who had developed metanephric adenoma with erythrocytosis and was served for cell culture. Significantly high concentrations of erythropoietin, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte-colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and IL-8 were detected in the cell culture supernatant. Southern hybridization showed specific positive signals for GM-CSF, G-CSF, IL-6, IL-8 and erythropoietin. The number of chromosomes was 46-XY without any structural abnormalities in cytogenetic analysis of the cultured cells.