Imatinib in the treatment of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a soft tissue tumor with tendency to recur locally and only rarely metastasizes to vital organs. Surgery with wide margins remains the standard treatment. DFSP is characterized by specific chromosomal abnormalities involving the platelet derived growth factor B locus (PDGFB). In the majority of cases a supernumerary ring chromosome containing amplified t(17; 22) translocation or a linear unbalanced t(17; 22) containing the COL1A1 -PDGFB fusion gene is present. This molecular event causes aberrant expression of a functional PDGFB leading to activation of PDGFR. Imatinib mesylate is a tyrosine kinase inhibitor with activity against activated PDGFR, and has significant activity against DFSP. Clinical evidence suggests that it has a role in locally advanced and metastatic disease and clinical trials are ongoing examining its role in this rare but potentially fatal sarcoma.