中川 義仁

Introduction. Colorectal cancer (CRC) is a leading cause of cancer deaths, closely linked to the intestinal microbiota and bile acid metabolism. Secondary bile acids, like deoxycholic and lithocholic acid, are associated with increased CRC risk due to their disruption of vital cellular functions. In contrast, isoallolithocholic acid (isoalloLCA) shows potential health benefits, highlighting the complex role of bile acids in CRC. A specific primer set was previously developed to amplify homologs of the 5α-reductase gene (5ar), which are involved in the biosynthesis of isoalloLCA, thereby enabling the estimation of abundance of 5ar (5ar levels) in the intestine.Hypothesis/Gap Statement. We hypothesized that 5ar levels in the intestine are associated with CRC.Aim. This study aimed to investigate intestinal 5ar levels and compare them across different stages of the adenoma-carcinoma sequence, providing insights into novel strategies for monitoring CRC risk.Methodology. DNA was extracted from intestinal lavage fluids (ILF) collected during 144 colonoscopies. Next-generation sequencing (NGS) was employed to examine the sequence of 5ar homologues, using a specific primer set on DNA from seven selected ILFs - four from carcinoma patients and three from individuals with non-neoplastic mucosa. Additionally, we used quantitative PCR (qPCR) to measure 5ar levels in all 144 DNA samples.Results. We conducted 144 colonoscopies and categorized patients according to the adenoma-cancer sequence: 52 with non-neoplastic mucosa, 69 with adenomas and 23 with carcinoma. Analysis of 292,042 NGS-derived 5ar sequences revealed the seven most prevalent amplicon sequence variants, each 254 base pairs in length. These closely matched or were identical to 5ar sequences in Bacteroides uniformis, Phocaeicola vulgatus and Phocaeicola dorei. Furthermore, qPCR analysis demonstrated significantly lower 5ar levels in the carcinoma group compared to those in the non-neoplastic mucosa group (P = 0.0004). A similar, though not statistically significant, trend was observed in the adenoma group (P = 0.0763), suggesting that 5ar levels decrease as CRC progresses.Conclusion. These findings indicate that PCR-based monitoring of 5ar levels in intestinal samples over time could provide a non-invasive, rapid and cost-effective method for assessing an increased risk of CRC.

Abstract Background and study aims Esophageal endoscopic submucosal dissection (ESD) has a higher complication rate than gastric ESD. Scissor-type devices, including the stag beetle (SB) knife, are reportedly safer and have shorter procedure times than tip devices. To clarify the characteristics of the SB knife, we compared the treatment outcomes of esophageal ESD with a tip-type knife to those with an SB knife combination. Patients and methods Between January 2016 and March 2023, clinical data from 197 lesions in 178 patients who underwent esophageal ESD were analyzed retrospectively. Every lesion was assigned to either the tip-type group or the SB group based on the devices with which the submucosa was initially dissected. We compared procedure time and complications and analyzed the risk of muscular exposure using multivariate analysis. Results Procedure time was not significantly different between the tip-type and SB groups (60.3±42.2 min vs. 58.8±29.1 min). The variation in procedure time was significant according to F test P=0.002). Incidence of muscular exposure was significantly lower in the SB group than in the tip-type group (24.5% vs. 11.1%, P=0.016). These differences were significant in resected specimens larger than 21 mm. Procedure time over 60 minutes (odds ratio [OR] 2.5, 95% confidence interval [CI]: 1.15–5.42, P=0.02) was a risk factor for muscular exposure, and submucosal dissection with an SB knife was a safety factor (OR 0.4, 95% CI: 0.18–0.89, P=0.02). Conclusions Performing esophageal ESD with an SB knife is a safe procedure with less variation in procedure time and less muscule exposure.

Helicobacter pylori induces DNA methylation in gastric mucosa, which links to gastric cancer (GC) risk. In contrast, CpG island methylator phenotype (CIMP) is defined as high levels of cancer-specific methylation and provides distinct molecular and clinicopathological features of GC. The association between those two types of methylation in GC remains unclear. We examined DNA methylation of well-validated H. pylori infection associated genes in GC and its adjacent mucosa and investigated its association with CIMP, various molecular subtypes and clinical features. We studied 50 candidate loci in 24 gastric samples to identify H. pylori infection associated genes. Identified loci were further examined in 624 gastric tissue from 217 primary GC, 217 adjacent mucosa, and 190 mucosae from cancer-free subjects. We identified five genes (IGF2, SLC16A2, SOX11, P2RX7, and MYOD1) as hypermethylated in H. pylori infected gastric mucosa. In non-neoplastic mucosa, methylation of H. pylori infection associated genes was higher in patients with GC than those without. In primary GC tissues, higher methylation of H. pylori infection associated genes correlated with CIMP-positive and its related features, such as MLH1 methylated cases. On the other hand, GC with lower methylation of these genes presented aggressive clinicopathological features including undifferentiated histopathology, advanced stage at diagnosis. H. pylori infection associated DNA methylation is correlated with CIMP, specific molecular and clinicopathological features in GC, supporting its utility as promising biomarker in this tumor type.

BACKGROUND/AIM: The combination of atezolizumab plus bevacizumab (Atz/Bev) has become widely used as a first-line therapy for advanced hepatocellular carcinoma (HCC). However, for post-Atz/Bev therapy, evidence on the outcomes of molecular targeted agents, such as lenvatinib, is limited. The present study aimed to assess the clinical effectiveness of lenvatinib on advanced HCC in patients who had previously undergone Atz/Bev treatment. PATIENTS AND METHODS: Twenty patients with HCC, who received lenvatinib after Atz/Bev treatment, were enrolled in the study. In particular, we examined the impact of adverse events (AEs), such as anorexia and general fatigue. During the treatment, lenvatinib dosages were adjusted or temporarily discontinued in response to AEs. Treatment outcomes were retrospectively evaluated. RESULTS: The objective response rate (ORR) and disease control rate (DCR) for lenvatinib treatment were 25.0% and 95.0%, respectively, according to the Response Evaluation Criteria in Solid Tumors. The median progression-free survival (PFS) was 6.0 months, and the median overall survival (OS) was 10.5 months. Eleven patients experienced anorexia or fatigue, leading to a reduction in the dose of lenvatinib but not to a significant difference in the time to drug discontinuation. Importantly, there were no significant differences between the 11 anorexia/fatigue-suffering patients and the nine other patients with regard to PFS and OS. CONCLUSION: Lenvatinib can be efficacious and safe for treating advanced HCC patients previously treated with Atz/Bev, and AEs such as anorexia and general fatigue can be effectively managed without losing lenvatinib's therapeutic benefits.