COL1A1-PDGFB Fusion Gene Detection Through Bulk RNA-Seq and Transcriptomic Features of Dermatofibrosarcoma Protuberans

Abstract

Background: Dermatofibrosarcoma protuberans (DFSP) is a cutaneous sarcoma with obscure origin and multidirectional differentiation. Application of RNA-Seq in the detection of COL1A1-PDGFB is still at early stages. Objective: We aim to test the efficacy of fusion gene detection using bulk RNA-Seq in DFSPs, explore altered molecular pathways and biological processes for evidences of tumor origin and cell identity shift. Materials and Methods: Dermatofibrosarcoma protuberans and normal dermis samples were acquired for RNA-Seq. Fusion gene detection was performed using STAR-Fusion. RNA-Seq 2G yielded differentially expressed genes. Altered pathways, key gene ontology terms, and similar cell/tissue types were identified with gene set enrichment analysis. xCell was used for cell types enrichment analysis. Results: 28/30 CD34(+) cases were positive for COL1A1-PDGFB. 406 upregulated and 543 downregulated genes were determined. Among the top 10 upregulated genes, 6 had neural distribution, function, or disease correlation. The upregulated genes were related to synapse, trans-synaptic signaling, neural development, and extracellular matrix. Similarities between DFSP and nervous system components were highlighted, with fibroblast cellular abundancy increased during xCell analysis. Conclusion: Bulk RNA-Seq provided with high detection rate of COL1A1-PDGFB. Dermatofibrosarcoma protuberans showed fibroblastic activity and neural features, which validated DFSP's fibroblast origin and tendency of neural differentiation.