FIGURE 4

Different degrees of appendiceal malignant transformation all exhibit high constitutive expression of MUC2. Normal appendix (A) exhibits focal expression of MUC2 in goblet cells (B); a pseudomyxoma peritonei implant from an appendiceal adenoma (C) expresses high levels of MUC2 (D); a borderline mucinous tumor of the appendix (E) similarly exhibits high MUC2 (F); a poorly differentiated signet ring adenocarcinoma arising within the appendix (G) similarly expresses high MUC2 (H). A, hematoxylin and eosin, x250; B, anti-MUC2, immunoperoxidase, x250; C, hematoxylin and eosin, x250; D, anti-MUC2, immunoperoxidase, x250; E, hematoxylin and eosin, x250; F, anti-MUC2, immunoperoxidase, x250; G, hematoxylin and eosin, x250; H, anti-MUC2, immunoperoxidase, x250