We have analyzed the abnormalities of growth factor and its receptor genes in human tumor samples by Southern hybridization. No remarkable gene amplification or rearrangement of platelet- derived growth factor (PDGF)-A chain, c-fms, c-ros or fyn was detected in 124 (22), 99 (21) and 72 (20) tumor cells (tissue species), respectively. Recently, we have isolated five genomic DNA clones homologous to the proto-oncogene family, which includes fms, kit and PDGF receptor.