Immunohistochemistry for benign and malignant SMTs includes positive reactivity to smooth muscle actin, muscle-specific actin, smooth muscle myosin, basal lamina components (including laminin and type IV collagen), and desmin, but their tumor cells are negative for cytokeratin, thyroglobulin, chromogranin, CEAm, and calcitonin [62, 67, 69]. This evidence concerns the gene CALCA and neoplasm.