Immunohistochemically, these tumor cells are positive for neuron-specific enolase (NSE) and human melanoma black 45 (HMB-45), but negative for myogenic markers (α-smooth muscle actin (α-SMA) and HHF-35), epithelial markers (AE1/AE3, CAM5.2), endocrine markers (synaptophysin, chromogranin A), and acinar markers (trypsin and α-1-antitrypsin) (Fig. 3). This evidence concerns the gene ACTA1 and neoplasm.