DPP4 and neoplasm: Gene ontology enrichment analysis of the 12 genes harboring protein-affecting somatic mutations revealed several biological processes such as muscle tissue/organ development (ZFPM2 and MEGF10), which is related to the mesothelium origin of this tumor, cell adhesion (DPP4, CDH9, CNTNAP4, MEGF10), response to mechanic stimulus (MEIS2, TRPA4), and response to abiotic stimulus (DPP4, MEIS2, TRPA1) (Additional file 3: Table S2).