Expression of Ki-67, p53, and K-ras in chronic pancreatitis and pancreatic ductal adenocarcinoma

Figure 1 H&E and immunohistochemical staining of normal pancreatic and ductal hyperplasia tissues. A: Normal interlobular duct surrounded by fibrous tissue is illustrated. Small cuboidal cells with basally located nuclei having intact nuclear polarity are seen in the inset. H&E stain, ×100; B: Ki-67 monoclonal Ab does not show reaction to almost epithelial cells. DAB and hematoxylin counter stain, ×100; C: Pancreatic duct hyperplasia with uniformly large columnar epithelial cells, which are more than twice as long as cytoplasm of normal cells and have mucinous metaplasia of the cytoplasm. The nuclei are small and basally located without atypia. H&E stain, ×100; D: Ki-67 monoclonal Ab shows a few proliferating nuclei of hyperplastic ductal epithelium. DAB and hematoxylin counter stain, ×100.

Figure 2 H&E and immunohistochemical staining of dysplastic tissues of the pancreatic duct. A: The nuclear enlargement, increased nuclear-to-cytoplasmic ratio, loss of nuclear polarity, pleomorphism, and nuclear overcrowding are seen. Several mitotic figures including atypical form are present. H&E stain, ×100; B: CEA monoclonal antibody shows positive reaction in the cytoplasmic membranes of dysplastic cells. DAB and hematoxylin counter stain, ×100; C: Ki-67 monoclonal antibody shows focally increased proliferating nuclei of dysplastic cells. DAB and hematoxylin counter stain, ×100; D: p53 monoclonal antibody shows focally positive reaction in the nuclei of dysplastic cells. AEC and hematoxylin counter stain, ×100.

Figure 3 H&E and immunohistochemical staining of pancreatic cancer. A: Moderate to poorly differentiated pancreatic adenocarcinoma with desmoplastic background. H&E stain, ×200; B: Immunohistochemical staining using CEA monoclonal antibody shows positive reaction in the cytoplasms of tumor cells. DAB and hematoxylin counter stain, ×200; C: Ki-67 monoclonal antibody shows significantly increased proliferation of nuclei of tumor cells. DAB and hematoxylin counter stain, ×200; D: Intense nuclear immunohistochemical staining of p53 in an invasive pancreatic adenocarcinoma. AEC and hematoxylin counter stain, ×200.

Figure 4 Cytoplasmic staining with K-ras is illustrated in both ductal hyperplasia and adjacent invasive adenocarcinoma. K-ras immunohistochemical stain, ×200.