COL1A1 and dermatofibrosarcoma protuberans: In 1997, Simon et al. were pioneers in postulating the presence of a fusion between the platelet-derived growth factor beta chain (PDGFB) and collagen alpha 1 (COL1A1) genes in dermatofibrosarcoma protuberance (DFSP) and giant cell fibroblastoma (GCF).