Immunohistochemically, the tumor cells were positive for vimentin, a mesenchymal marker, but negative for epithelial markers (CK AE1/AE3, CK7, and CK20), myogenic markers (desmin and α-smooth muscle actin), neurogenic markers (CD56 and S-100), lymphoid markers (CD45 and CD30), and endothelial markers (CD31). The gene discussed is PECAM1; the disease is neoplasm.