CDX2 and malignant colon neoplasm: Immunohistochemical analysis with cytokeratin 20 (ck 20, clone ks 20.8, Novocastra Menarini), ck 7 (clone ov-tl 12/30, Dako), and cdx2 (clone AMT 28, Novocastra Menarini) defined two distinct profiles of positivity: ck20 positive, ck7 negative, and cdx2 positive for the colonic cancer, and ck20 negative, ck7 positive, and cdx2 negative for the liver (Figure 3).