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

Area of Science:

• Oncology
• Dermatology
• Molecular Biology

Background:

• Kaposi's sarcoma (KS) is a malignancy associated with various forms, including AIDS-related, classical, and pseudo-KS.
• Previous in vitro studies suggested that autocrine secretion of basic fibroblast growth factor (bFGF) might drive KS tumor cell proliferation.

Purpose of the Study:

• To investigate the in vivo expression of basic fibroblast growth factor (bFGF) in different types of Kaposi's sarcoma (KS).
• To determine if KS tumor cells exhibit autocrine secretion of bFGF.

Main Methods:

• Immunoperoxidase staining was performed on cryostat sections of ten KS cases (five AIDS-KS, one classical KS, four pseudo-KS).
• Affinity-purified anti-bFGF antibodies were used to detect bFGF antigen expression.
• Staining patterns were compared between KS tumor cells and normal skin biopsies.

Main Results:

• Basic fibroblast growth factor (bFGF) was strongly expressed in basal and suprabasal keratinocytes of normal skin.
• bFGF was generally absent or showed only very faint staining in the endothelial cells and spindle cells of the KS neoplasms.
• These findings contrast with previous in vitro observations.

Conclusions:

• The in vivo data strongly suggest that KS tumor cell proliferation is unlikely to be explained by an autocrine secretion mechanism of bFGF.
• The study provides evidence against the previously proposed autocrine hypothesis for KS growth.
• Further research is needed to elucidate the actual mechanisms driving KS proliferation in vivo.