CpG island promoter hypermethylation of Ras association domain family 1A gene contributes to gastric carcinogenesis.

Methylation rates of the Ras association domain family 1A gene (RASSF1A) have been variously reported as between 7.5 and 66.7% in gastric carcinoma tissues. The role of this gene in gastric cancer also remains to be fully elucidated. The present study aimed to investigate whether promoter hypermethylation of RASSF1A occurs in gastric adenocarcinoma tissues and gastric cancer cell lines, and to determine the effects of RASSF1A in gastric carcinoma cell lines. The results showed a methylation­specific band only in SNU­719, MKN28 and AGS human gastric cancer cells (indicating full methylation), none of which exhibited RASSF1A expression. By contrast, SNU­16, MKN­45 and KATO­III human gastric carcinoma cells exhibited methylation as well as unmethylation­specific bands (indicating partial methylation), and all displayed positive or weakly positive expression of RASSF1A. Bisulfite sequencing in AGS and SNU­719 cells revealed that virtually all CpG sites were densely methylated. When SNU­719, MKN­28 and AGS cells were treated with the demethylating agent 5­aza­2'­deoxycytidine, RASSF1A gene expression was restored and the methylation­specific polymerase chain reaction pattern was altered in all three cell lines. Transfection of a plasmid expressing RASSF1A into AGS and SNU­719 cells significantly inhibited cell proliferation. Exogenous RASSF1A also reduced the expression of cyclin D1 and phospho­retinoblastoma protein, and increased that of p27 as demonstrated by western blot analysis. Furthermore, RASSF1A expression was significantly reduced (P=0.048) and the methylation rate was elevated in gastric adenocarcinoma tissues, compared with those in adjacent healthy intestinal metaplasia (34.6 vs. 66.7%, P=0.029). The present study indicated that epigenetic silencing of RASSF1A is frequently caused by promoter hypermethylation in gastric cancer cell lines as well as in gastric adenocarcinoma tissues, which may contribute to gastric carcinogenesis.

Prevalence and endoscopic features of eosinophilic esophagitis in patients with esophageal or upper gastrointestinal symptoms.

OBJECTIVE: This study was aimed to evaluate the prevalence of eosinophilic esophagitis (EoE) among patients with esophageal or upper gastrointestinal (UGI) symptoms. METHODS: Patients with esophageal or UGI symptoms including dysphagia food impaction, acid regurgitation, heartburn, chest pain, epigastric pain, nausea and/or vomiting were prospectively collected. The enrolled patients responded to a symptomatic questionnaire and underwent an esophagogastroduodenoscopy and esophageal biopsies. Supportive endoscopic findings of EoE (ring-like appearance, liner furrows, whitish papules, shearing or friability) were recorded. EoE was diagnosed if patients had chronic UGI or esophageal symptoms, the esophageal biopsy showed ≥15 eosinophils/high-power field and were unresponsive to 2-3 weeks of proton pump inhibitors. RESULTS: A total of 122 patients were enrolled and supportive endoscopic findings were found in 31 (25.4%) patients [whitish papules: 19 (15.6%), ring-like appearance: 8 (6.6%), linear furrows: 5 (4.1%)]. One patient had a simultaneous ring-like appearance and linear furrows. EoE was diagnosed in 8 (6.6%) patients and supportive endoscopic findings and past history of gastroesophageal reflux disease, allergic rhinitis and atopic dermatitis were more common in EoE positive than EoE negative patients. The diagnostic yield of endoscopic findings was 40.0% (2/5) in linear furrows, 25.0% (2/8) in ring-like appearance and 15.8% (3/19) in whitish papules. CONCLUSION: Prevalence of EoE among patients with esophageal or UGI symptoms was 6.6%. Linear furrows and ring-like appearance had a relatively high diagnostic value.

The effects of photodynamic therapy in upper-gastrointestinal malignant diseases.

Photodynamic therapy (PDT) is a promising new modality that utilizes the combination of a photosensitizing chemical and visible light for the management of various solid malignancies, including gastrointestinal (GI) cancer. PDT has some advantages over chemotherapy in terms of its greater safety and lower toxicity in the treatment of malignant lesions. However, PDT has not been used widely for treating upper GI cancer due to its relatively low cost-effectiveness and anatomical characteristics of the GI system. Nevertheless, PDT may be an effective alternative therapy for early upper-GI cancer patients who are at a high risk of curative surgical resection or systemic chemotherapy. In some clinical studies, PDT for various upper GI cancer showed positiveresults. To improve the efficacy of PDT for upper GI cancer, development of photosensitezer and light delivery system is needed.

Pancreatic tuberculosis masquerading as pancreatic serous cystadenoma.

Solitary pancreatic involvement of tuberculosis is rare, especially in an immunocompetent individual, and it may be misdiagnosed as pancreatic cystic neoplasms. Pancreatic cystic neoplasms are being identified in increasing numbers, probably because of the frequent use of radiology and advances in endoscopic techniques. However, they are composed of a variety of neoplasms with a wide range of malignant potential, and it is often difficult to differentiate pancreatic tuberculosis mimicking cystic neoplasms from benign or malignant pancreatic cystic neoplasms. Non-surgical diagnosis of pancreatic tuberculosis is inconclusive and continues to be a challenge in many cases. If so, then laparotomy should be employed to establish the diagnosis. Therefore, pancreatic tuberculosis should be kept in mind during the differential diagnosis of solitary cystic masses in the pancreas. We report a patient who had solitary pancreatic tuberculosis masquerading as pancreatic serous cystadenoma.