Dermatofibrosarcoma protuberans: A retrospective study of clinicopathologic features and related Akt/mTOR, STAT3, ERK, cyclin D1, and PD-L1 expression.

Background: Little is known regarding oncoproteins other than platelet-derived growth factor subunit B in dermatofibrosarcoma protuberans (DFSP). Moreover, the risk factors for worse prognosis are controversial.

Objective: We sought to determine the clinicopathologic features and key factors for adverse outcome in DFSP, including the implication of expression of protein kinase B (Akt)/mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3), extracellular signal regulated kinase (ERK), cyclin D1, and programmed death ligand 1 (PD-L1).

Methods: Clinicopathologic and immunohistochemical analyses were performed for 44 DFSPs having wide local excision and 92 dermatofibromas as controls.

Results: Compared with the 35 nonrecurrent DFSPs, the 9 recurrent DFSPs exhibited larger tumor size, deeper invasion beyond the subcutis, and more diverse histologic subtype. The fibrosarcomatous subtype revealed frequent mitotic figures and a high cyclin D1-positive index. The 2 metastatic DFSPs (1 each of the fibrosarcomatous and myxoid subtypes) demonstrated 4 and 11 instances of local recurrence, respectively, as well as larger tumor size, deeper invasion beyond the subcutis, and high expression of cyclin D1. Expression of Akt/mTOR, STAT3, ERK, and PD-L1 ranged from none or low in the primary skin lesions to high in the corresponding metastatic sites. Akt/mTOR and ERK were expressed more frequently in DFSP than in dermatofibroma.

Limitations: Lack of information on patients before hospital evaluation.

Conclusion: Complex factors beyond fibrosarcomatous subtype may portend local recurrence or metastasis. Akt/mTOR, STAT3, ERK, and PD-L1 may be associated with development and/or progression of DFSP.