More than 90% of<unk>  tumors have the chromosomal translocation t(17;22). The translocation fuses the collagen gene (COL1A1) with the platelet-derived growth factor (PDGF) gene. The fibroblast, the cell of origin of this tumor, expresses the fusion gene in the belief that it codes for collagen. However, the resulting fusion protein is processed into a mature platelet-derived growth factor which is a potent growth factor. Fibroblasts contain the receptor for this growth factor. Thus the cell "thinks" it is producing a structural protein, but it creates a self-stimulatory growth signal. The cell divides rapidly and tumor forms. The tissue is often positive for CD34.
Dermatofibrosarcoma protuberans
Dermatofibroma
Elastofibroma dorsi
Angiokeratoma
Lymphangioma circumscriptum
Chondroid syringoma
Pseudomelanoma
Sarcoma botryoides