Identification of an acidic fibroblast growth factor-like activity in a mesoblastic nephroma

An acidic fibroblast growth factor-like activity was detected in a primary mesoblastic nephroma. Identification was based upon Northern blot analysis of renal tumor RNA and by a biochemical characterization of the growth factor activity. The activity extracted from the tumor stimulated DNA synthesis in both mouse fibroblasts and bovine endothelial cells. This activity was heat-sensitive and enhanced in the presence of heparin. The extract activity bound to immobilized immobilized heparin, eluting at 1.2 M NaCl, and cross-reacted with antiserum to recombinant acidic fibroblast growth factor. We also present evidence for acidic fibroblast growth factor-like molecules in normal immature human kidney, although the amount of the activity detected is less than that in the mesoblastic nephroma. These data suggest that acidic fibroblast growth factor-like activity is present in the developing normal human kidney, and that some renal tumors can continue to express a similar activity.