Expression of basic fibroblast growth factor and vascular endothelial growth factor in primary and metastatic melanoma from the same patients

Basic fibroblast growth factor (bFGF) and vascular endothelial growth facto r (VEGF) are both recognized as stimulators of migration and angiogenesis d uring the progression of melanoma, However, the timepoints during tumour pr ogression at which the expression of these angiogenic factors is most essen tial is still controversial. Using immunohistochemical analyses, melanoma c ells were found to express bFGF in 18 out of 19 primary tumours and in 13 o ut of 20 metastases, Eleven of the 19 primary tumours and 15 of the 20 meta stases were found to contain VEGF-positive melanoma cells; five of the 19 p atients showed no VEGF-expressing melanoma cells at all. This indicates tha t VEGF expression may be a later event in the progression of melanoma than bFGF expression. Reverse transcription-polymerase chain reaction (RT-PCR) a nalyses of the melanoma cell lines showed that all cell lines were positive for both bFGF and VEGF mRNA, CD31-positive endothelial cells were primaril y seen in the metastases (17 out of 20). Only four of the primary tumours c ontained CD31-positive cells, but these tumours expressed bFGF as well as V EGF, indicating that both angiogenic factors may be important for the forma tion of vessels in tumours. (C) 1999 Lippincott Williams & Wilkins.