COL6A3 and dermatofibrosarcoma protuberans: However, additional genes (CSPG2, PTK2B, COL1A2, COL6A3, PDGFD, EMILIN2, P53, and MDM2) and signaling pathways (RAS-MARK and PI3k-Akt-mTOR) have been identified in the pathogenesis of DFSP.