Figure 3.

A: Colon carcinoma from a patient with HNPCC. This patient was shown to have a TGFBR2 mutation. Tumor cells contain both nuclear and cytoplasmic Dpc4. Immunohistochemistry using anti-Dpc4 antibody, counterstained with hematoxylin. B: A sporadic colorectal carcinoma completely lacking expression of Dpc4. The stromal and inflammatory cells within the desmoplastic stroma serve as internal controls that express Dpc4. Immunohistochemistry using anti-Dpc4 antibody, counterstained with hematoxylin. C: Sporadic colorectal adenocarcinoma with strong expression of Dpc4 in tumor cell nuclei and cytoplasm. The lymphoid cells (arrow) in the lamina propria also label for Dpc4.