Expression of basic fibroblast growth factor (bFGF) in Kaposi's sarcoma: an immunohistologic study

Ten cases of Kaposi's sarcoma (KS) including five AIDS-KS, one classical KS, and four pseudo-KS (acroangiodermatitis) were investigated for their expression of basic fibroblast growth factor. Antigen expression was demonstrated by immunoperoxidase staining of cryostat sections with affinity-purified anti-bFGF antibodies. It was found that bFGF was strongly expressed in basal and suprabasal keratinocytes, which were also intensively stained in normal skin biopsies. The growth factor was generally absent from the endothelial cells and spindle cells of the neoplasms. These cell types exhibited a very faint staining in a small number of lesions. The studies provide strong evidence that proliferation of KS tumor cells may not be explained by autocrine secretion mechanism of the growth factor, which has been suggested in previous reports with in vitro cultured KS cell lines.