Molecularly targeted treatment for dermatofibrosarcoma protuberans.

Traditionally, treatment for dermatofibrosarcoma protuberans (DFSP), a rare cutaneous tumor that is locally aggressive, has been limited to wide surgical excision with negative margins. Although not usually metastatic, DFSP has significant potential for recurrence and interference in local structures. The pathogenesis of DFSP stems from a chromosomal rearrangement involving chromosomes 17 and 22, in which the collagen 1alpha1 gene is fused to the gene for platelet-derived growth factor (PDGF) B-chain. The resultant deregulated expression of PDGFB leads to continuous activation of the PDGF receptor beta (PDGFRbeta) protein-tyrosine kinase that promotes DFSP tumor cell growth. Imatinib is a potent and specific inhibitor of several protein-tyrosine kinases, including the PDGFRs. Preclinical investigations and clinical reports have shown the efficacy of imatinib in DFSP. Imatinib may provide an alternative for the treatment of unresectable or partially resectable tumors, thereby possibly improving the effectiveness of surgery.