Immunohistochemical staining of tumor cells in ductal structures expressed the same staining characteristics as intercalated ductal cells [positive for keratin, CEA, S-100, and CD117 (c-Kit)], and staining of cells surrounding the pseudocystic lumen suggested myoepithelial differentiation (positive for S-100 and actin and heterogeneously positive for keratin).[13–15]. The gene discussed is KIT; the disease is neoplasm.