Yu Sasaki

Helicobacter pylori ( H. pylori ) infects the gastric epithelium of approximately half of the global population, and is a well-known risk factor for developing gastric cancer. Despite the clinical significance of H. pylori infection, many genetic factors that contribute to susceptibility remain unidentified. While it is well-established that H. pylori infection can result in gastritis and peptic ulcers, which may progress to gastric cancer, its causal link to other diseases remains unclear. We performed the genome-wide association study (GWAS) for anti- H. pylori IgG antibody titers, which were validated as a surrogate marker for H. pylori infection by the correlation with clinical traits, followed by gene-based and pathway analyses, involving up to 140,863 individuals. This included 56,967 in the discovery phase, and 68,211 in the replication phase from Japanese cohorts, and an additional 15,685 from European populations in a cross-ancestry meta-analysis. We reveal significant associations between H. pylori infection and polymorphisms in the Human Leukocyte Antigen (HLA) class II region within the Major Histocompatibility Complex (MHC), as well as genes related to innate immunity, including CCDC80 , NFKBIZ , TIFA , PSCA , and TRAF3 . Mendelian randomization (MR) analysis revealed that genetic liability to H. pylori infection has both positive and negative causal relationships with a variety of diseases, including autoimmune-related diseases such as Type 1 diabetes, Hashimoto’s disease, atopic dermatitis, as well as traits like body height and weight. These genetic findings strongly support the notion that genetic liability to H. pylori infection influences not only gastrointestinal diseases, but also a broader spectrum of health issues, thereby providing valuable insights for public health strategies and personalized medicine approaches.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory syndrome characterized by dense IgG4-positive plasma-cell infiltrate and progressive fibrosis. Small intestinal involvement is uncommon, and its clinicopathological spectrum remains unclear. Herein, we describe two older individuals with small intestinal lesions rich in IgG4-positive plasma cells. Case 1 was a 73-year-old woman with known orbital and pancreatic IgG4-RD who developed mild ileal narrowing, detected on surveillance imaging, and elevated serum IgG4 (214 mg/dL). Case 2 was an 87-year-old woman without prior IgG4-RD who presented with bowel obstruction caused by a tight ileal stricture, normal serum IgG4 level (59 mg/dL), and no other organs affected. In both patients, histological examination revealed dense lymphoplasmacytic infiltration, with IgG4/IgG ratios exceeding 40%. Although hyper-IgG4-emia and multiorgan involvement commonly trigger diagnostic suspicion, these cases demonstrate that IgG4-rich inflammation can arise as a solitary manifestation in the small intestine, and may escape detection unless specific immunostaining is conducted. Sequential organ involvement is also possible, underscoring the need for longitudinal follow-up. IgG4‑positive plasma‑cell infiltration should be included in the differential diagnosis of unexplained small‑intestinal ulcers or strictures—even when serum IgG4 is normal and systemic features of IgG4‑RD are absent—as histological confirmation can guide timely immunosuppressive or surgical management.

X-linked agammaglobulinemia (XLA) is associated with an increased risk of gastrointestinal cancers including gastric cancer (GC). We herein report the case of a 30-year-old male patient with XLA who developed GC and extensive atrophic gastritis. He tested positive in the urea breath test, thus indicating the presence of Helicobacter pylori. Distal gastrectomy and chemotherapy were performed without any complications; however, the died two years after this diagnosis. Immunoglobulin deficiency makes these patients susceptible to progressive atrophic gastritis and the associated risk of GC. Therefore, patients with XLA are advised to undergo an evaluation for Helicobacter pylori infection as well as monitoring for GC.

A 47-year-old woman presented with multiple gastric tumors, each up to 10 mm in diameter, in the gastric body and fundus without mucosal atrophy. White spots and numerous transparent, light-brownish, small, and rounded spots were observed in the background gastric mucosa. Biopsy specimens obtained from the tumors revealed gastric neuroendocrine tumors. The patient exhibited hypergastrinemia and achlorhydria and tested negative for serum parietal cell antibody, intrinsic factor antibody, and Helicobacter pylori infection. Moreover, no additional lesions were detected on imaging. These findings were inconsistent with Rindi’s classification. The tumor was resected via endoscopic submucosal resection. Histopathological examination revealed gastric neuroendocrine tumors G2 infiltrating the submucosa with no atrophy of the gastric mucosa, dilated fundic glands, parietal cell protrusions, and hyperplasia of enterochromaffin-like cells. Immunohistochemically, the parietal cells were negative for both α- and β-subunits of H⁺/K⁺ ATPase, suggesting parietal cell dysfunction. A genomic variant was identified in adenosine triphosphatase H⁺/K⁺ transporting subunit alpha. After 7 years of treatment, there was no evidence of residual or metastatic lesions. Modification of adenosine triphosphatase H⁺/K⁺ transporting subunit alpha may be a significant factor in the pathogenesis of multiple gastric neuroendocrine tumors in the context of gastric parietal cell dysfunction.

Objectives: Narrow light observation is currently recommended as an alternative to Lugol chromoendoscopy (LCE) to detect esophageal squamous cell carcinoma (ESCC). Studies revealed little difference in sensitivity between the two modalities in expert settings; however, these included small numbers of cases. We aimed to determine whether blue light imaging (BLI) without magnification is satisfactory for preventing misses of ESCC.Methods: This was a post‐hoc analysis of a multicenter randomized controlled trial targeting patients at high risk of ESCC in expert settings. In this study, BLI without magnification followed by LCE was performed. The evaluation parameters included: (i) the diagnostic abilities of ESCC; (ii) the endoscopic characteristics of lesions with diagnostic differences between the two modalities; and (iii) the color difference between cancerous and noncancerous areas in BLI and LCE.Results: This study identified ESCC in 49 of 699 cases. Of these cases, nine (18.4%) were missed by BLI but detected by LCE. In per‐patient analysis, the sensitivity of BLI was lower than that of LCE following BLI (83.7% vs. 100.0%; P = 0.013), whereas the specificity and accuracy of BLI were higher (88.2% vs. 81.2%; P < 0.001 and 87.8% vs. 82.5%; P < 0.001, respectively). No significant endoscopic characteristics were identified, but the color difference was lower in BLI than in LCE (21.4 vs. 25.1; P = 0.003).Conclusion: LCE following BLI outperformed BLI in terms of sensitivity in patients with high‐risk ESCC. Therefore, LCE, in addition to BLI, would still be required in screening esophagogastroduodenoscopy even by expert endoscopists.

ObjectivesClinical outcomes of endoscopic submucosal dissection (ESD) for esophageal squamous cell carcinoma (ESCC) with esophageal varices (EVs) are obscure. We aimed to elucidate the clinical outcomes of ESD for ESCC with EVs in a multicenter, retrospective study. MethodsWe established a retrospective cohort of 30 patients with ESCC complicating EVs, who underwent ESD at 11 Japanese institutions. Rates of en bloc resection and R0 resection, procedure time, and adverse events were evaluated as indicators of the feasibility and safety of ESD. Additional treatment, recurrence, and metastasis of the lesions were evaluated as indicators of the long-term efficacy of ESD. ResultsPortal hypertension was caused by cirrhosis, of which alcohol was the most common cause. En bloc resection was achieved in 93.3% and R0 resection in 80.0% of the patients. The median procedure time was 92 min. Adverse events included a case of uncontrolled intraoperative bleeding leading to discontinuation of ESD and a case of esophageal stricture due to extensive resection. During the follow-up period of a median for 42 months, a patient with local recurrence and another patient with liver metastasis were observed. One patient died of liver failure after receiving chemoradiotherapy as an additional treatment after ESD. No patient died of ESCC. ConclusionThis multicenter, retrospective cohort study demonstrated the safety and efficacy of ESD for ESCC with EVs. Further studies are needed to establish appropriate treatment methods for EVs before ESD and additional treatments for patients with insufficient ESD.

Objectives: Blue light imaging (BLI) and linked color imaging (LCI) are superior to conventional white light imaging for detecting esophageal squamous cell carcinoma (ESCC). Hence, we compared their diagnostic performances in ESCC screening.Methods: This open‐labeled, randomized controlled trial was performed at seven hospitals. Patients with a high risk of ESCC were randomly assigned to the BLI group (BLI followed by LCI) and LCI group (LCI followed by BLI). The primary end‐point was the detection rate of ESCC in the primary mode. The main secondary end‐point was its miss rate in the primary mode.Results: In total, 699 patients were enrolled. The detection rate of ESCC did not significantly differ between the BLI and LCI groups (4.0% [14/351] vs. 4.9% [17/348]; P = 0.565); however, the number of patients with ESCC tended to be smaller in the BLI group (19 vs. 30). Notably, the miss rate of ESCC was lower in the BLI group (26.3% [5/19] vs. 63.3% [19/30]; P = 0.012) and LCI detected no ESCCs missed by BLI. The sensitivity was higher in BLI (75.0% vs. 47.6%; P = 0.042); on the other hand, the positive predictive value in BLI tended to be lower (28.8% vs. 45.5%; P = 0.092).Conclusions: The detection rates of ESCC did not significantly differ between BLI and LCI. Although BLI may have the potential to be advantageous over LCI for the diagnosis of ESCC, it is still unclear whether BLI is superior to LCI, and a further large‐scale study is needed.Trial registration: Japan Registry of Clinical Trials (jRCT1022190018‐1).

Obesity is a major risk factor for colorectal cancer (CRC). Sustained hyperglycemia destabilizes tumor suppressor ten-eleven translocation (TET) 2, which is a substrate of AMPK, thereby dysregulating 5-hydroxymethylcytosine (5-hmC). However, the role played by this novel pathway in the development of obesity-related CRC is unclear. In this study, we aimed to evaluate the expression levels of TET2 and 5-hmC in obesity-related CRC and the effects of TET2 expression on the proliferation of CRC cells. To this end, surgically resected CRC samples from seven obese patients (Ob-CRC) and seven non-obese patients (nOb-CRC) were analyzed, and expression levels of the TET family and 5-hmC were compared between the groups. A decrease was observed in TET2 mRNA levels and 5-hmC levels in Ob-CRC compared to that in nOb-CRC. Furthermore, we used CRC cell lines to investigate the relationship between insulin, proliferation, and TET expression and AMPK. In cell lines, glucose and insulin treatments suppressed the expression of TET2 and increased cell proliferation. Downregulation of TET2 using siRNA also induced cell proliferation. An AMPK activator inhibited insulin- or glucose-stimulated cell proliferation and restored TET2 expression. We propose the AMPK-TET2-5-hmC axis as a novel pathway and potential therapeutic target in obesity-related CRC development.