Sohachi Nanjo

Demonstration of the usefulness of epigenetic cancer risk prediction by a multicentre prospective cohort study

Background Epigenetic alterations accumulate in normal-appearing tissues of patients with cancer, producing an epigenetic field defect. Cross-sectional studies show that the degree of the defect may be associated with risk in some types of cancer, especially cancers associated with chronic inflammation. Objective To demonstrate, by a multicentre prospective cohort study, that the risk of metachronous gastric cancer after endoscopic resection (ER) can be predicted by assessment of the epigenetic field defect using methylation levels. Design Patients with early gastric cancer, aged 40–80 years, who planned to have, or had undergone, ER, were enrolled at least 6 months after Helicobacter pylori infection discontinued. Methylation levels of three preselected genes (miR-124a-3, EMX1 and NKX6-1) were measured by quantitative methylation-specific PCR. Patients were followed up annually by endoscopy, and the primary endpoint was defined as detection of a metachronous gastric cancer. Authentic metachronous gastric cancers were defined as cancers excluding those detected within 1 year after the enrolment. Results Among 826 patients enrolled, 782 patients had at least one follow-up, with a median follow-up of 2.97 years. Authentic metachronous gastric cancers developed in 66 patients: 29, 16 and 21 patients at 1–2, 2–3 and ≥3 years after the enrolment, respectively. The highest quartile of the miR-124a-3 methylation level had a significant univariate HR (95% CI) (2.17 (1.07 to 4.41); p=0.032) and a multivariate-adjusted HR (2.30 (1.03 to 5.10); p=0.042) of developing authentic metachronous gastric cancers. Similar trends were seen for EMX1 and NKX6-1. Conclusions Assessment of the degree of an epigenetic field defect is a promising cancer risk marker that takes account of life history.

High impact of methylation accumulation on metachronous gastric cancer: 5-year follow-up of a multicentre prospective cohort study

We recently published in your journal a 3-year multicentre prospective cohort study demonstrating the usefulness of an epigenetic cancer risk marker for gastric metachronous cancers.1 This study achieved the first proof of concept of epigenetic cancer risk diagnosis in any type of cancer but, due to the short follow-up period, a relatively small number of events were observed, resulting in a marginally significant difference (p=0.042). It was anticipated that a longer follow-up could lead to a clearer difference and HR with a smaller 95% CI. We now report the 5-year follow-up data, which show highly significant results. Among the 826 enrolled patients, 795 patients received annual follow-ups by endoscopy for a median period of 5.46 years (IQR: 3.95–6.09). By the end, 133 patients had developed a metachronous gastric cancer. Among them, 116 patients developed a metachronous gastric cancer detected 1 year after the enrolment (authentic metachronous cancer). Statistical analyses were conducted in the same manner as previously …

Autophagy impairment by Helicobacter pylori-induced methylation silencing of MAP1LC3Av1 promotes gastric carcinogenesis

Helicobacter pylori (H. pylori) infection induces methylation silencing of tumor suppressor genes causing gastric carcinogenesis. Impairment of autophagy induces DNA damage leading to genetic instability and carcinogenesis. We aimed to identify whether H. pylori infection induced methylation silencing of host autophagy‐related (Atg) genes, impairing autophagy and enhancing gastric carcinogenesis. Gastric mucosae were obtained from 41 gastric cancer patients and 11 healthy volunteers (8 H. pylori‐uninfected and 3 H. pylori‐infected). Methylation status of Atg genes was analyzed by a methylation microarray and quantitative methylation‐specific PCR (qMSP); mRNA expression was assessed by quantitative reverse transcription PCR (qRT‐PCR). Cell proliferation, migration and invasion were assessed in normal rat gastric epithelial cells. Gene knock‐down was performed by siRNA. Autophagy was assessed by western blotting. Of 34 Atg genes, MAP1LC3A variant 1 (MAP1LC3Av1) and ULK2 were identified by methylation microarray analysis as exhibiting specific methylation in H. pylori‐infected mucosae and gastric cancer tissues. Methylation silencing of MAP1LC3Av1 was confirmed by qMSP, qRT‐PCR and de‐methylation treatment in two gastric cancer cell lines. Knock‐down of map1lc3a, the rat homolog of the human MAP1LC3Av1, inhibited autophagy response and increased cell proliferation, migration and invasion in normal rat gastric epithelial cells, despite the presence of map1lc3b, the rat homolog of the human MAP1LC3B gene important for autophagy. Furthermore, MAP1LC3Av1 was methylation‐silenced in 23.3% of gastric cancerous mucosae and 40% of non‐cancerous mucosae with H. pylori infection. MAP1LC3Av1 is essential for autophagy and H. pylori‐induced methylation silencing of MAP1LC3Av1 may impair autophagy, facilitating gastric carcinogenesis.

Amrubicin Monotherapy for Patients with Platinum-Refractory Gastroenteropancreatic Neuroendocrine Carcinoma

Objective. Patients with gastroenteropancreatic neuroendocrine carcinoma (NEC) have a poor prognosis. Platinum-based combination chemotherapy is commonly used as first-line treatment; however, the role of salvage chemotherapy remains unknown. This study aimed to analyze the efficacy and safety of amrubicin monotherapy in patients with platinum-refractory gastroenteropancreatic NEC. Methods. Among 22 patients with advanced gastroenteropancreatic NEC, 10 received amrubicin monotherapy between September 2007 and May 2014 after failure of platinum-based chemotherapy. The efficacy and toxicity of the treatment were analyzed retrospectively. Results. Eight males and two females (median age, 67 years (range, 52–78)) received platinum-based chemotherapy, including cisplatin plus irinotecan (n = 7, 70%), cisplatin plus etoposide (n = 2, 20%), and carboplatin plus etoposide (n = 1, 10%) before amrubicin therapy. Median progression-free survival and overall survival after amrubicin therapy were 2.6 and 5.0 months, respectively. Two patients had partial response (20% response rate), and their PFS were 6.2 months and 6.3 months, respectively. Furthermore, NEC with response for amrubicin had characteristics with a high Ki-67 index and receipt of prior chemotherapy with cisplatin and irinotecan. Grade 3-4 neutropenia and anemia were observed in four and five patients, respectively. Conclusion. Amrubicin monotherapy appears to be potentially active and well-tolerated for platinum-refractory gastroenteropancreatic NEC.

Transient receptor potential vanilloid 4 (TRPV4) silencing in Helicobacter pylori-infected human gastric epithelium

Helicobacter pylori (HP) infection induces methylation silencing of specific genes in gastric epithelium. Various stimuli activate the nonselective cation channel TRPV4, which is expressed in gastric epithelium where it detects mechanical stimuli and promotes ATP release. As CpG islands in TRPV4 are methylated in HP‐infected gastric epithelium, we evaluated HP infection‐dependent changes in TRPV4 expression in gastric epithelium.

Neuroendocrine Carcinoma of the Stomach: A Response to Combination Chemotherapy Consisting of Ramucirumab Plus Paclitaxel

Extrapulmonary neuroendocrine carcinoma (NEC) is a rare disease, and there is no standard chemotherapy. A 73-year-old man was diagnosed with advanced gastric NEC. He received chemotherapy of irinotecan plus cisplatin, and amrubicin monotherapy. After failure of second-line chemotherapy, he received ramucirumab plus paclitaxel; this treatment was chosen because vascular endothelial growth factor 2 was strongly expressed in the tumor endothelial cells. After two cycles, his NEC had markedly reduced in size, and he continued with this treatment for over eight months. In this case, the combination of an anti-angiogenic inhibitor and a cytotoxic agent was highly effective for gastric NEC.

Multiple Colon Ulcers with Typical Small Intestinal Lesions Induced by Non-Steroidal Anti-Inflammatory Drugs

The diagnosis of NSAID-induced colon ulcers is difficult when the distribution or endoscopic findings are not typical. An 83-year-old woman was transferred to our hospital for hemorrhagic diarrhea. Colonoscopy showed multiple ulcers in the entire colon, particularly longitudinal ulcers in the transverse colon. These were unusual for NSAID-induced colopathy, although she had been on meloxicam. However, capsule endoscopy revealed multiple scars and erosions, characteristic of NSAIDs users. The final diagnosis was NSAID-induced enteropathy, and all lesions were in remission after meloxicam discontinuation. We herein emphasize the value of an endoscopic assessment of the entire digestive tract in the diagnosis of NSAID-induced mucosal lesions.

1645PMOLECULAR CHARACTERIZATION OF GASTRIC NEUROENDOCRINE CARCINOMA BASED ON EXTENSIVE SEQUENCE VARIATION AND GENOME-WIDE METHYLATION ANALYSIS

ABSTRACT Aim: Neuroendocrine cancer (NEC) of the stomach is a rare type of cancer that is often diagnosed at an advanced stage and with poor prognosis. Its molecular characterization associated with its pathogenesis and therapeutic targets are poorly understood, although chemotherapy based on small cell type of lung cancer is recommended. In this study, we aimed to clarify the molecular characterization of gastric NEC and to find NEC-specific alterations in comparison with adenocarcinoma. Methods: Twenty samples from gastric cancers with advanced stage (11 adenocarcinomas and 9 NECs) and paired non-cancerous mucosa as controls were obtained by endoscopic biopsy. Analysis of sequence variations of 55 cancer-related genes was performed using the Ion AmpliSeq Panel Kit (Life Technologies), and analysis of DNA methylation was performed using the Infinium HumanMethylation 450 BeadChip array, covering 482,421 CpG sites (Illumina). DNA methylation and sequencing variation was confirmed using methylation-specific PCR and dideoxy sequencing. Results: Extensive mutation analysis revealed mutations of tumor suppressor genes (TP53 and CDKN2A) were frequently detected, whereas any oncogene mutation was not detected in gastric NECs. However, ERBB2 and KRAS were amplified and overexpressed, which were therapeutic targets. Comprehensive methylation analysis revealed 842 gene promoters were methylated, and gene silencing associated with neuronal differentiation (p=7.68E-21) and regulation of transcription (P=1.24E-21) were significantly enriched in gastric NECs. Among these genes, 13 genes were identified as NEC-specific methylations in comparison with adenocarcinoma, and TLE1 and HNF1B were known to be cancer-related genes in blood and ovarian cancers. Conclusions: To the best of our knowledge, this is the first study in which both genetic and epigenetic alterations were extensively analyzed in gastric NECs. Gene alteration with therapeutic targets was detected in NEC, and cell differentiation defects and cell cycle progression with DNA methylation are suggested to be involved in carcinogenesis of gastric NECs. Disclosure: All authors have declared no conflicts of interest.

Seven days triple therapy for eradication of Helicobacter pylori does not alter the disease activity of patients with inflammatory bowel disease

Background/Aims The influences of Helicobacter pylori eradication therapy on the disease course of inflammatory bowel disease (IBD) are still unclear. We therefore conducted a multicenter, retrospective cohort study to evaluate the safety of H. pylori eradication therapy for IBD patients. Methods IBD patients with H. pylori eradication from 2005 to 2015 (eradication group) and control patients (non-eradication group; 2 paired IBD patients without H. pylori eradication matched with each eradicated patient) were included. IBD exacerbation (increased/additional IBD drug or IBD-associated hospitalization/surgery) and disease improvement based on the physicians’ global assessment were investigated at baseline, and at 2 and 6 months after eradication or observation. Results A total of 429 IBD (378 ulcerative colitis, 51 Crohn’s disease) patients, comprising 144 patients in the eradication group and 285 patients in the non-eradication group, were enrolled at 25 institutions. IBD exacerbation was comparable between groups (eradication group: 8.3% at 2 months [odds ratio, 1.76; 95% confidence interval, 0.78–3.92; P=0.170], 11.8% at 6 months [odds ratio, 1.60; 95% confidence interval, 0.81–3.11; P=0.172]). Based on the physicians’ global assessment at 2 months, none of the patients in the eradication group improved, whereas 3.2% of the patients in the non-eradication group improved (P=0.019). Multivariate analysis revealed that active disease at baseline, but not H. pylori eradication, was an independent factor for IBD exacerbation during 2 months’ observation period. The overall eradication rate was 84.0%–comparable to previous reports in non-IBD patients. Conclusions H. pylori eradication therapy does not alter the short-term disease activity of IBD.

Multiple Synchronous Sporadic Gastrointestinal Stromal Tumors in the Stomach and Jejunum

A 77-year-old patient was admitted to our hospital for the further examination of melena. A computed tomography scan detected two submucosal tumors (SMTs) in the stomach and jejunum. Double-balloon endoscopy revealed the presence of a delle on the jejunal SMT, suggesting that the SMT was the origin of the gastrointestinal bleeding. Both tumors were surgically resected and subsequently diagnosed via histology as gastrointestinal stromal tumors (GISTs). Furthermore, the two GISTs had different mutations in the c-kit gene, suggesting that they were derived from different clonal origins. This report depicts an extremely rare case of multiple synchronous sporadic GISTs in the stomach and jejunum.