Immunohistochemically (IHC) staining revealed that the tumor cells were diffusely positive for cytokeratin (CK) 5/6, p40, desmocollin 3, claudin 4, and MOC31, whereas they were negative for WT1, D2-40, S100 protein, GFAP, CD34, c-kit, NUT, and calponin. The gene discussed is CLDN4; the disease is neoplasm.