IMPAIRED EXPRESSION OF STEM-CELL FACTOR IN DERMATOFIBROMA FIBROBLASTS

The number of mast cells is increased in dermatofibroma lesions and pl ays a role in the induction of fibrosis or its proliferation, We have investigated stem cell factor expression in solitary and multiple derm atofibromas by immunohistochemical staining. We also analyzed messenge r RNA (mRNA) expression of stem cell factor in dermatofibroma tissues and cultured fibroblasts derived from dermatofibromas, using reverse t ranscriptase polymerase chain reaction. We found inmunoreactive stem c ell factor in keratinocytes, dermal fibroblasts, melanocytes and hair follicles. Unexpectedly, a reduced expression of immunoreactive stem c ell factor in dermatofibroma fibroblasts was observed in solitary and multiple type. However, mRNA expression of stem cell factor was detect ed both in the dermatofibroma tissue and cultured dermatofibroma-deriv ed fibroblasts, We speculate that the altered expression of stem cell factor of tumor cells in dermatofibroma lesions can be associated with the tumor cell proliferation and induction of dermatofibroma.