CDX2 and neoplasm: Immunohistochemistry showed the tumor cells to be positive for CK7 (Fig. 2D); most tumor cells were found to be positive for p40 (Fig. 2E), ck5/6, p63 and negative for PAX8, CD10, RCC, CAIX, TTF1, S100, CDX2, SATB2, CK20, calponin, HMB-45, Melan A, SOX10, WT-1, Carteinin, D2–40, and SMA.