Stable and strong expression of basic fibroblast growth factor in naevus cell naevus contrasts with aberrant expression in melanoma.

Abstract

It has been proposed that basic fibroblast growth factor (bFGF) is an autocrine growth factor of melanoma cells, in contrast with normal melanocytes where bFGF acts as a paracrine growth factor. As this notion is mostly based on the different requirements for bFGF in cultures of benign and malignant pigment cells in vitro, we performed an immunohistochemical study to examine bFGF expression in vivo, using paraffin sections from naevus cell naevi (NCN) and malignant melanoma (MM). All the NCN (n = 7) showed strong and homogeneous expression of bFGF protein, whereas the primary MMs (n = 5) showed heterogeneous expression, with a population of negative cells. Metastatic MMs (n = 5) also showed heterogeneous expression, and had a greater population of negative cells. These results suggest that bFGF has some, as yet unidentified, role in the growth of benign NCN, and that overexpression of bFGF is neither a prerequisite for melanoma genesis nor for progression to metastatic MM.