Activation of the platelet-derived growth factor receptor [beta] (PDGFRB), a transmembrane tyrosine kinase, by fusion of the gene encoding for its ligand, PDGFB
, with COL1A1 (collagen, type 1, a 1) renders dermatofibrosarcoma protuberans responsive to targeted therapy with tyrosine kinase inhibitors, such as imatinib mesylate.
118,119) Fluorescence in situ hybridization has been used to confirm PDGFB
split-apart probes on interphase cells, including paraffin-embedded tissue.
Copy gain of PDGFB occurs in a subset of tumors showing no evidence of mutated BRAF or rearranged ret, suggesting that copy gain of PDGFB may underlie the increased expression of platelet-derived growth factor described recently in the literature.
Table 8 demonstrates that gains of PDGFB (22q13), TP 73 (1p36.
1 (epidermal growth factor receptor, a protein tyrosine kinase), FGF4 on 11q13 (fibroblast growth factor 4, a classical activator of the MAPK pathway), and PDGFB on 22q13.