H. pylori infection has been found in over 80% of patients with GIM (37)

which can then be identified by using the Das-1 antibody which stains H. pylori in gastric associated GIM (36). Gastric LBH589 in vivo adenocarcinoma (GA) GA is the second most common cancer worldwide with the highest rates in Asia. It is more common in males and has been associated with risk factors such as low socioeconomic status, cigarette smoking, nitrites, chronic gastritis and H. pylori (41-43). The majority of gastric adenocarcinomas is located in the pylorus and antrum (50-60%), followed by the cardia (25%), and the body or fundus (15-25%) and may be exophytic, flat or ulcerated. There are two classifications of GA, Inhibitors,research,lifescience,medical the intestinal Inhibitors,research,lifescience,medical type, which has well-formed glands lined by columnar to cuboidal epithelial cells (Figure 2), and the diffuse type which shows single to poorly formed nests of cells growing in an infiltrate pattern (signet ring cell carcinoma) (Figure 3A) (43,44). Intestinal type GA shows variable expression of CK7 (Figure 2B), CK20 (Figure 2C), CDX-2 (Figure 2D), MUC1, and MUC5AC (45-47). Diffuse type of GA usually

develops de novo, and is not associated with H. pylori induced IM. Over 70% of cases of the diffuse type of GA are positive for CDX-2 (Figure 3B), CK7 (Figure 3C), HepPar-1 Inhibitors,research,lifescience,medical (Figure 3D) and variable expression of CK20 (Figure 3E), MUC2 and MUC5AC, but negative for MUC1 and E-cadherin (Figure 3F) (48,49). Cases of poorly differentiated adenocarcinoma with prominent lymphoplasmacytic stroma may also be positive for EBV (50,51). Figure 2 Histologic and immunohistochemical features of gastric adenocarcinoma – intestinal type. A. Gastric adenocarcinoma-intestinal Inhibitors,research,lifescience,medical type; B. CK7 shows variable expression in tumor cells; C. CK20 with variable expression; D. CDX-2 diffuse nuclear positivity … Figure 3 Histologic and immunohistochemical Inhibitors,research,lifescience,medical features of gastric adenocarcinoma – diffuse type/signet

ring cell carcinoma. A. Gastric adenocarcinoma- diffuse type/signet ring cell carcinoma; B. Variable CDX-2 positivity; C. CK7 positivity; D. HepPar-1 expression; … Tumors of the upper gastrointestinal tract such as Barrett’s esophagus, esophageal adenocarcinoma and gastric adenocarcinoma may show similar immunohistochemical findings, Table 1 compares each of their unique immunohistochemical profile (52,53). Table 1 Comparison of immunohistochemical Bay 11-7085 profiles of Barrett’s, esophageal and gastric adenocarcinoma Gastrointestinal stromal tumor (GIST) Stromal tumors comprise the majority of primary nonepithelial neoplasms in the stomach, and GIST is the most common GI mesenchymal neoplasm. GIST may occur anywhere within the GI tract but is most common in the stomach (60%) (53), with prognosis varying according to their location (54). Histologically, GISTs resemble smooth muscle tumors with spindle or epithelioid cells.