Schwannoma also expresses glial fibrillary acidic protein (GFAP) and CD57 (Leu 7), but lack expression of CD117, CD34, and DOG-1, markers which can help differentiate them from certain gastrointestinal tumors that may also stain positive for S-100 (13, 14). The gene discussed is B3GAT1; the disease is digestive system neoplasm.