Expression of fibroblast growth factors and their receptors in acquired immunodeficiency syndrome—associated Kaposi sarcoma tissue and derived cells

Background. Fibroblast growth factors (FGF), such as basic FGF, have been implicated in the development of Kaposi sarcoma (KS) in vitro. The expression of several genes of the FGF family and their receptors in KS tumor lesions and KS‐derived cells were evaluated. Methods. Cultures of KS‐derived cells were established. The expression of FGF family members and their receptors in these cells and in fresh biopsies from KS tumors was evaluated by reverse transcription polymerase chain reaction (RTPCR). The RTPCR products were confirmed by nucleotide sequencing. Results. The expression of basic FGF and FGF receptor‐1 (flg) was detected in all the samples tested. Acidic FGF (aFGF) and FGF‐5 were detected in two of six and four of six KS tumor specimens, respectively, whereas both of these growth factors were expressed in all of the cell cultures, including six KS‐derived cell cultures and human endothelial cells and smooth muscle cells. FGF‐6 was expressed in two of six KS tumor specimens, but was not expressed in any of the cultured KS cells. Like flg, bek was expressed in all tissue samples and KS‐derived cell cultures except in one KS specimen obtained from the patient's tongue showing expression of a high level of FGF‐6. Conclusions. These results suggest that the expression of FGF in KS tumors with the coexpression of FGF receptors may provide a basis for autocrine and paracrine mechanisms contributing to the development of KS.