DES and melanoma: Positive controls were used for all markers as follows: HMB-45 and Melan-A – melanoma; RCC – renal cell carcinoma; S100 – schwannoma; desmin, smooth muscle actin, muscle-specific actin, and myogenin – GI smooth muscle; CD117 – GI mast cells and Cajal cells; cytokeratins – GI epithelial tissue; vimentin – GI mesenchymal tissue; and CD34 – tonsillar endothelial tissue.