Induction of growth factor RNA expression in human malignant melanoma: markers of transformation.

Alteration in the expression of growth factors is widely accepted as being one of several critical defects in the generation of the malignant cell. In the present study, 19 human metastatic melanoma cell lines were compared to 14 normal human foreskin melanocyte cell lines for the production of RNA transcripts specific for 11 different growth factors. Using the extremely sensitive technique of polymerase chain reaction to amplify growth factor-specific complementary DNAs, we analyzed the following: transforming growth factor (TGF) types alpha, beta 1, beta 2, and beta 3, acidic (a) fibroblast growth factor (FGF), basic (b) FGF, FGF-5, keratinocyte growth factor (KGF), HST, and platelet-derived growth factor (PDGF) types A and B. There were clear distinctions among the patterns of growth factor RNA expression by normal melanocytes and malignant melanoma cells. The prototypic melanocyte pattern of expression included TGF beta 1, TGF beta 3, and KGF. A subset of melanocyte cell lines also expressed PDGFA transcripts. In contrast, melanoma cells characteristically expressed RNA transcripts of TGF beta 1, TGF beta 2, TGF beta 3, TGF alpha, bFGF, KGF, and PDGFA. Subsets of melanoma cell lines also expressed aFGF, FGF-5, and PDGFB. The results presented indicated that TGF beta 2, TGF alpha, and bFGF may be particularly important in melanomagenesis and that these, as well as FGF-5, aFGF, and PDGFB, can be used as markers of transformation in this tumor type.