Figure 1.

Expression of cytokeratin and apomucin for histological classification. Intestinal-type carcinomas are composed of well-formed tubular to elongated glands and complex cribriform areas indistinguishable from colorectal adenocarcinomas (A), and they are immunohistochemically stained by the CK20 antibody (B) but show no reaction to the MUC1 antibody (C). Pancreatobiliary-type carcinomas mostly consist of simple or branching glands surrounded by strikingly desmoplastic stroma (D) negative for CK20 (E) and positive for MUC1 antibody (F) (A, D: hematoxylin and eosin stain, ×20; B, C, E: ×20;F ×50).