Renotropic growth factor found in cancer patient sera after removal of cancer-bearing kidney

It is a well established fact that the removal or injury of one kidney results in renal growth of the other kidney [1]. This compensatory renal growth is controlled by a humoral serum factor(s) which is induced by reduction of renal functions [2–5]. Therefore, this humoral factor, so-called renotropin or renotropic growth factor, should also stimulate growth of the healthy area of the physically injured or disease-bearing kidney in addition to the other kidney.In experimental animals the extent of renal growth is known to be related directly to the portion of the kidney mass (partially or subtotally) removed [6]. Thus, the amount of renotropic growth factor produced should be proportional to the amount of renal function lost. In cancer-bearing kidneys, the enlargement and infiltration of cancer in kidneys theoretically should produce the renotropic growth factor and stimulate healthy tissue to grow. When a cancer-bearing kidney is removed, the lost proportion of renal function should be responsible for the amount of renotropic growth factor produced.In this communication we demonstrate the renotropic growth factor in renal cancer patient sera after uninephrectomy and an assay procedure for renotropic growth factor using noncancerous cells from a cancer-bearing kidney