Retrospective study of COL1A1-PDGFB fusion gene-positive dermatofibrosarcoma protuberans in Kumamoto University

Abstract

Dermatofibrosarcoma protuberans (DFSP) is a rare neoplasm derived from fibroblasts and tumorigenic mechanism is mainly defined by the formation of a fusion gene between the α‐helix domain of the collagen type 1 (COL1A1 ) gene and the platelet‐derived growth factor‐β (PDGFB ) gene. We investigated the fusion site of COL1A1/PDGFB gene and its relationship with clinical findings in 30 patients with DFSP treated at our hospital. COL1A1/ PDGFB fusion was detected in 83% of DFSP patients. The breakpoint in the PDGFB gene was before exon 2 in all patients, while that in the COL1A1 gene was after exon 25 in five patients, exon 32 in four patients, exon 39 and 46 in two patients, and exons 7, 8, 14, 28, 29, 31, 33, 35, 37, 39, 43, 47 in one patient. In our cohort study, there was no correlation between the COL1A1 breakpoint and clinical findings. To the best of our knowledge, no report to date has described a case of DFSP with exon 28 in the COL1A1 gene.