Upregulation of TGF-β1 and basic FGF in elastofibroma: an immunohistochemical analysis

Elastofibroma is a rare tumour that occurs in the subscapular space, and it typically presents in middle-aged and older individuals. The aetiology of elastofibroma remains unknown. Recent, sporadic reports have shown, immunohistologically, that fibroblasts in elastofibroma may produce abnormal elastic and collagen fibres through the action of transforming growth factor-beta (TGF-β), a factor that promotes fibroblast proliferation. However, that finding lacked quantitative measurements and controls. Therefore, in this study, we performed quantitative, immunohistochemical analyses of TGF-β1 and basic fibroblast growth factor (bFGF) in three elastofibromas, and we compared them to ten dermatofibromas and keloids, and five normal skin. In elastofibroma specimens, 16-59 % fibroblasts were positive for TGF-β1 in the cytoplasm, compared to 96 % in dermatofibroma, 93 % in keloid and 2 % in normal dermis specimens. Also, in elastofibroma specimens, 26-67 % of fibroblasts were positive for bFGF in the cytoplasm, compared to 97 % in dermatofibroma, 97 % in keloid, and 22 % in normal dermis specimens. Intriguingly, the tumour size and growth rate were proportional to the percentage of cells positive for bFGF. Finally, greater levels of bFGF expressions in fibroblasts were associated with larger sized elastofibromas. These results suggested that elastofibroma development depended on high expression of TGF-β1 and bFGF.