Shuichi Yokosawa

Essential role of gastric gland mucin in preventing gastric cancer in mice.

Gastric gland mucin secreted from the lower portion of the gastric mucosa contains unique O-linked oligosaccharides (O-glycans) having terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc). Previously, we identified human α1,4-N-acetylglucosaminyltransferase (α4GnT), which is responsible for the O-glycan biosynthesis and characterized αGlcNAc function in suppressing Helicobacter pylori in vitro. In the present study, we engineered A4gnt(-/-) mice to better understand its role in vivo. A4gnt(-/-) mice showed complete lack of αGlcNAc expression in gastric gland mucin. Surprisingly, all the mutant mice developed gastric adenocarcinoma through a hyperplasia-dysplasia-carcinoma sequence in the absence of H. pylori infection. Microarray and quantitative RT-PCR analysis revealed upregulation of genes encoding inflammatory chemokine ligands, proinflammatory cytokines, and growth factors, such as Ccl2, Il-11, and Hgf in the gastric mucosa of A4gnt(-/-) mice. Further supporting an important role for this O-glycan in cancer progression, we also observed significantly reduced αGlcNAc in human gastric adenocarcinoma and adenoma. Our results demonstrate that the absence of αGlcNAc triggers gastric tumorigenesis through inflammation-associated pathways in vivo. Thus, αGlcNAc-terminated gastric mucin plays dual roles in preventing gastric cancer by inhibiting H. pylori infection and also suppressing tumor-promoting inflammation.

A genomewide DNA microsatellite association study of Japanese patients with autoimmune hepatitis type 1

Genetic predisposition to type 1 autoimmune hepatitis (AIH) is linked mainly to HLA class II genes. We previously searched the whole HLA region for AIH susceptibility genes using microsatellite markers and found only HLA‐DR/DQ to be a candidate region for this suspected multifactorial disease. As such, the aim of this study was to broaden our search and screen the whole genome for additional genes that might contribute to type 1 AIH susceptibility. Eighty‐one patients with type 1 AIH (15 men, 66 women, average age 55.9) and 80 healthy sex‐ and age‐matched Japanese controls were enrolled in this study. We performed a case‐control association study using 400 polymorphic microsatellite markers with an average spacing of 10.8 cM distributed throughout the whole genome. Two markers, one on chromosome 11 (D11S902, Pc = 0.013) and one on chromosome 18 (D18S464, Pc = 0.008), were revealed to have statistically significant associations with AIH. An additional 7 markers (D2S367, D6S309, D9S273, D11S1320, D16S423, D17S938, and D18S68) were also found to be candidate susceptibility regions. In addition, our results showed there were 17 regions that may contain genes of resistance to AIH. No specific markers were detected in HLA‐DR4‐negative patients, and no differences were seen in the clinical courses of patients (severe versus mild to moderate). Conclusion: This first genomewide scan of Japanese AIH patients revealed at least 26 candidate AIH susceptibility or resistance regions other than HLA class II loci. These results also suggested that the products of several genes interact to determine heritable susceptibility to AIH. (HEPATOLOGY 2007;45:384–390.)

Helicobacter pylori-Negative Primary Rectal MALT Lymphoma: Complete Remission after Radiotherapy

Rectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare condition. Although the majority of patients undergo surgical resection, a definitive treatment for rectal MALT lymphoma has not yet been established. In the present study, we report the outcome of radiotherapy in 3 patients with rectal MALT lymphoma. Our cohort ranged from 56 to 65 years of age. The male/female ratio was 1:2, and all patients were in stage I (Lugano classification) of the disease. Endoscopic findings revealed elevated lesions resembling submucosal tumors in 2 patients, and a sessile elevated lesion with a nodular surface in 1 patient. One of the 3 patients underwent magnifying endoscopy with crystal violet staining that demonstrated a type I pit pattern (Kudo’s classification) lesion with a broad intervening area caused by the upthrust of the tumor from the submucosa. All patients tolerated radiotherapy at doses of 30 Gy without major complications and achieved complete remission. Follow-up ranged from 13 to 75 months (mean 51.0 months), revealing no recurrence of MALT lymphoma. As such, we propose radiotherapy to be a safe and effective means for treating rectal MALT lymphoma.

Reduced expression of αGlcNAc in Barrett's oesophagus adjacent to Barrett's adenocarcinoma – a possible biomarker to predict the malignant potential of Barrett's oesophagus

Gastric gland mucin contains O‐glycans exhibiting terminal α1,4‐linked N‐acetylglucosamine residues (αGlcNAc). Recently we demonstrated that mice deficient in αGlcNAc in gastric gland mucin develop gastric adenocarcinoma spontaneously, indicating that αGlcNAc is a tumour suppressor for gastric cancer. However, the role of αGlcNAc in Barretts oesophagus (BO) remains unknown. In this study, we investigated whether reduced αGlcNAc expression in BO is associated with development of Barretts adenocarcinoma (BAC).

A case of Helicobacter heilmannii-associated primary gastric mucosa-associated lymphoid tissue lymphoma achieving complete remission after eradication

A 46-year-old man underwent gastrointestinal endoscopy while visiting the hospital for a general physical check-up. Coarse mucosa in the antrum with superficial erosions was found by endoscopic gastrointestinal examination, but no atrophic changes were seen in the corpus. Histopathological examination of gastric biopsy specimens revealed mucosa-associated lymphoid tissue (MALT) lymphoma. Although Helicobacter pylori was not detected in our patient, H. heilmannii was identified histologically and by polymerase chain reaction analysis, resulting in the diagnosis of H. heilmannii-associated gastric MALT lymphoma. We successfully eradicated H. heilmannii and achieved complete remission of gastric MALT lymphoma by antibiotic therapy. H. heilmannii usually causes milder gastritis than H. pylori, but it has been more closely associated with MALT lymphoma. As such, when H. pylori infection is excluded in patients with gastric MALT lymphoma, physicians should next consider the possibility of H. heilmannii. Furthermore, our research suggests that eradication therapy is effective for treatment of localized H. heilmannii-associated gastric MALT lymphoma.

Total pancreas divisum caused by ventral pancreas malrotation showing biliary pancreatitis

A 52-year-old man was admitted to our hospital complaining of abdominal pain. A blood test showed high serum levels of biliary enzymes and amylase. Surprisingly, a computed tomography scan revealed complete separation of the ventral and dorsal pancreas and swelling of the ventral pancreas with choledocholithiasis. Surgical cholecystectomy was performed to remove the bile duct stones after endoscopic removal was unsuccessful. The complete separation of the pancreatic parenchyma caused by ventral pancreas malrotation seen in this case is extremely rare, and may provide important information regarding embryologic development, deformity, and malfunction of the pancreas.