Prostate Stem Cell Antigen Gene Polymorphism Is Associated with H. pylori-related Promoter DNA Methylation in Nonneoplastic Gastric Epithelium

Genome-wide association study identified two functional SNPs associated with gastric cancer especially the diffuse type. The first was a polymorphism (rs2294008) in prostate stem cell antigen (PSCA), and the other was a polymorphism (rs4072037) in mucin 1 (MUC1). DNA methylation is associated with gastric cancer and Helicobacter pylori (H. pylori)-induced gastritis, while hypermethylation of promoter CpG island (CGI) is a common characteristic of enlarged-fold gastritis induced by H. pylori, a risk factor of diffuse-type gastric cancer. We evaluated the association between PSCA and MUC1 polymorphisms with H. pylori--related promoter CGI methylation in the nonneoplastic gastric mucosa. PSCA rs2294008 C/T and MUC1 rs4072037 A/G polymorphisms were genotyped in 410 cancer-free subjects in relation to promoter CGI methylation status of three candidate genes, of which the methylation status is associated with H. pylori infection (IGF2, MYOD1, and SLC16A12). Methylation levels of all three genes were significantly higher in subjects with PSCA rs2294008 T/T compared with the PSCA rs2294008 C/C (all P < 0.05). Such associations were more enhanced in H. pylori-positive subjects (all P < 0.01). The multivariate analysis demonstrated that PSCA C/T [OR, 2.37; 95% CI (confidence interval), 1.06-5.29; P = 0.035] and T/T genotypes (OR, 3.2; 95% CI, 1.41-7.25; P = 0.005) were significantly associated with methylation-high gastric mucosa as independent factors. MUC1 rs4072037 A/G polymorphism was not associated with methylation status of all three genes. PSCA C/T and T/T genotypes are associated with H. pylori-related promoter DNA methylation in the gastric mucosa.Impact: Our observations provided the evidence that PSCA polymorphism influence the susceptibility to gastric cancer through DNA methylation induction.

Development of a Comorbidity Index to Identify Patients With Small Bowel Bleeding at Risk for Rebleeding and Small Bowel Vascular Diseases

BACKGROUND & AIMS

We aimed to establish a comorbidity index for small bowel vascular diseases (SBVD) associated with small bowel bleeding (SBB) and recurrent bleeding.

METHODS

We performed a retrospective analysis of 404 patients diagnosed with SBB via double-balloon enteroscopy, at 2 hospitals in Japan from June 2003 through July 2016. We collected data on comorbidities, computed Charlson Comorbidity Index and anticoagulation and risk factors in atrial fibrillation (ATRIA) scores, and analyzed associations with SBVD, rebleeding, and overall survival associated with bleeding and/or comorbidities. We used these data to develop a comorbidity index to identify patients at risk for SBVD, rebleeding, and reduced survival time. We validated our findings in a separate, prospective cohort of 88 patients with SBB.

RESULTS

We developed a weighted index (the Ohmiya index) that identified patients who developed SBVD with an area under the receiver operating characteristic (AUROC) curve of 0.7758; this value was higher than that of the Charlson index score (0.6828; P < .0001) or ATRIA score (0.6728; P < .0001) alone. Among the 51 patients taking oral anticoagulants, there was no significant difference in AUROCs for the Ohmiya score (0.5254) vs the outcomes registry for better informed treatment score (0.5857; P = .4300). In the retrospective cohort, the Ohmiya index identified patients with SBVD with 68% sensitivity (93/137), 84% specificity (223/267), and 78% accuracy (316/404); in the validation cohort, these values were 63% (22/35), 85% (45/53), and 76% (67/88), respectively. Onset age <50 years and index score <2 identified patients with Meckel's diverticulum and Crohn's disease with 53% accuracy. Onset age ≥50 years and index score <2 identified patients with inflammatory diseases, drug-induced injuries, or tumors with 72% accuracy. An index score ≥2 identified patients with SBVD with 68% accuracy, regardless of age. Among patients with Ohmiya index scores ≥2, 33% had rebleeding; among patients with scores <2, 15% had rebleeding (hazard ratio for score ≥2, 1.729; 95% CI, 1.038-2.882; P = .0355).

CONCLUSION

We developed an index, based on comorbidities and age of onset of SBB, that identified patients at risk for rebleeding and vascular disease (for example, enteroscopic hemostasis for SBVD, medication for inflammatory diseases, surgery with enteroscopic tattooing for tumors and diverticula). UMIN: 000025693.

Eradication of Helicobacter pylori Induces Immediate Regressive Changes in Early Gastric Adenocarcinomas

OBJECTIVE

Helicobacter pylori eradication is expected to prevent gastric cancer. However, morphological alterations after eradication often hinder accurate diagnosis. Therefore, we evaluated endoscopic and histological changes in gastric tumors after eradication of H. pylori in a time-dependent manner.

METHODS

We classified 144 cases of endoscopic submucosal dissection (ESD) of early gastric cancer into the following categories: (i) patients positive for H. pylori with no eradication history, (ii) patients positive for H. pylori who underwent ESD 2 months after eradication, (iii) patients negative for H. pylori with an eradication history of at least 6 months before ESD, and (iv) patients negative for H. pylori with an unknown history. We compared endoscopic and histological factors between the groups.

RESULTS

The characteristics of cancers positive for H. pylori were exploding shape, superficial high-grade atypical epithelium, and a surface proliferating zone. H. pylori eradication induced a series of endoscopic and histological changes, including shape -depression, appearance of surface regenerative and lower-grade atypical epithelium, and a downward shift of the proliferative zone within a period as short as 2 months.

CONCLUSION

H. pylori eradication rapidly causes cancer regression and leads to tumor shrinkage, diminished atypism, and shortened proliferative zone, resulting in drastic morphological changes.

Association of genetic polymorphisms in DNMT3A with the progression of gastric mucosal atrophy and susceptibility to gastric cancer in Japan

The aim of the present study was to investigate whether single nucleotide polymorphisms in the DNMT3A gene are associated with susceptibility to gastric cancer in the Japanese population. The present case-control study examined the associations between single nucleotide polymorphisms (rs6733868 and rs13428812) in DNMT3A and cancer susceptibility in 343 patients with gastric cancer and 708 subjects without gastric malignancies on upper gastro-duodenal endoscopy. Of 708 controls, 409 were classified into two groups histologically: 99 cases with and 310 cases without gastric mucosal atrophy. Overall, homozygosity for the DNMT3A rs6733868 minor allele was significantly associated with a reduced risk of gastric cancer (odds ratio [OR], 0.621; 95% confidence interval [CI], 0.402-0.958; P=0.031), especially of the intestinal type (OR, 0.494; 95% CI, 0.274-0.890; P=0.019). In subjects >60 years, rs6733868 minor allele homozygosity was significantly associated with gastric cancer susceptibility. Carriers of the rs6733868 minor allele had a reduced risk of severe gastric mucosal atrophy (OR, 0.495; 95% CI, 0.299-0.826; P=0.0069). In addition, the number of minor alleles of both rs6733868 and rs13428812 was significantly correlated with the risk of Helicobacter pylori (HP) infection (P=0.0070 and P=0.0050, respectively). However, rs13428812 was not associated with severe gastric mucosal atrophy or gastric carcinogenesis. The present results suggest that DNMT3A polymorphisms serve roles in the progression from HP infection to gastric mucosal atrophy and gastric carcinogenesis in terms of degree and manner.

Molecular subtyping of gastric cancer combining genetic and epigenetic anomalies provides distinct clinicopathological features and prognostic impacts

Both genetic and epigenetic abnormalities play important roles in gastric cancer (GC) development. We investigated whether the molecular subtypes of gastric cancer by combining genetic and epigenetic anomalies define its clinicopathological features and prognosis. The CpG island methylator phenotype (CIMP), MLH1 methylation, TP53, and KRAS mutation statuses were characterized in 214 GCs in relation to their clinicopathological features and prognosis. The molecular subtypes based on CIMP and TP53 hot spot mutation status (R175, G245, R248, R273, and R282) best predicted prognosis of GC. These subtypes contained 120 CIMP-positive (CIMP+) TP53 hot spot mutation-negative (TP53 hot spot-) cases, 81 CIMP-negative (CIMP-) TP53 hot spot- cases, 8 CIMP+TP53 hot spot mutation-positive (TP53 hot spot+) cases, and 5 CIMP- TP53 hot spot+ cases. The CIMP-TP53 hot spot+ group presented the worst overall survival (OS) and progression-free survival (PFS), followed by the CIMP+TP53 hot spot+, CIMP-TP53 hot spot- and CIMP+TP53 hot spot- groups (both P < 0.0001). These subtypes also correlated well with several aggressive clinicopathological features in that order. The molecular subtypes were independent factors for predicting overall survival (hazard ratio = 1.66, 95% CI = 1.07-2.57, P = 0.006). The molecular subtypes combining the CIMP and TP53 hot spot mutation status provide distinct clinicopathological features and prognostic impacts in GC.

DNA methylation accumulation in gastric mucosa adjacent to cancer after Helicobacter pylori eradication

Molecular irreversibleness with Helicobacter pylori (H. pylori) infection might have a role in gastric tumorigenesis after H. pylori eradication. We performed comprehensive DNA methylation profiling of gastric mucosa after H. pylori eradication with or without gastric cancer. Using four different groups of biopsies obtained from gastric body without history of H. pylori infection (Hp-), gastric body without cancer after H. pylori eradication (cancer-free body), gastric body with early gastric cancer diagnosed after H. pylori eradication (EGC body) and their paired samples from adjacent mucosa of cancer (EGC ADJ), methylation status of five candidate genes (MYOD1, SLC16A12, IGF2, RORA and PRDM5) was examined by the bisulfite pyrosequencing. An Infinium Methylation EPIC BeadChip array was also used to characterize the methylation status of greater than 850,000 CpG sites. The EGC ADJ group showed highest methylation levels of five candidate genes among the four groups of biopsies. In the gastric body (cancer-free body + EGC body), methylation levels were significantly decreased in patients with longer period after eradication, while such association was not observed in EGC ADJ group. Hyper methylated samples were associated with shorter telomere, an indicator for rapid cell turnover, and higher DNMT1 protein expression, an enzyme related to methyl transfer reaction. The genome-wide methylation analysis demonstrated strikingly higher methylation levels especially at CpG islands in the EGC ADJ group. Exclusively hypermethylated promoter CpG islands in the same group frequently coded zinc finger proteins. Our data show that DNA methylation accumulation is associated with molecular irreversibleness and gastric carcinogenesis after H. pylori eradication.

Polymorphism rs7521584 in miR‑429 is associated with the severity of atrophic gastritis in patients with Helicobacter pylori infection

The aim of the present study was to investigate an association of genetic polymorphism (rs7521584) located in miR‑200a‑200b‑429 cluster, which has tumor suppressor and pro‑inflammatory function, with the development of gastric mucosal atrophy and metaplasia as a pre‑malignant condition. Gastric mucosa samples were obtained from the antrum of 393 patients with no malignancies. The rs7521584 genotype was determined using the polymerase chain reaction‑single‑strand conformation polymorphism analysis method. The degree of gastritis was assessed histologically in all subjects and serum levels of pepsinogen (PG) I/II were quantified in 123 out of 393 patients. Patients with an atrophy score ≥1 and metaplasia score ≥1 were classified into the atrophic gastritis group (AG group). The rs7521584 TT genotype was significantly associated with the development of atrophic gastritis [odds ratio (OR), 2.41; 95% confidence interval (CI), 1.10‑5.25; P=0.027), particularly in patients with H. pylori infection (OR, 3.31; 95% CI, 1.35‑8.12; P=0.0089). In addition, in patients younger than 60 years of age, this genotype was associated with atrophic gastritis (OR, 3.15; 95% CI 1.03‑9.61; P=0.044)]. In patients with H. pylori infection, the metaplasia score was significantly higher in the TT homozygote compared with the GG+GT genotype. In the rs7521584 TT homozygote, serum PG I/II ratio was significantly reduced with increasing age (P=0.0084). No significant trend was identified between the GG+GT genotype and age. The results of the current study indicated that the rs7521584 minor allele homozygote was associated with the development of chronic gastritis under the influence of H. pylori‑induced inflammation, particularly with the severity of metaplastic alterations.

Unusual growth of an Epstein-Barr virus-associated differentiated early-stage gastric carcinoma: A case report

Epstein-Barr virus (EBV) infection is involved in a subset of gastric carcinoma (GC) cases, and is associated with distinct clinicopathological features. The present study reports a unique case of EBV-associated early-stage GC compared with the other cases experienced in our hospital. A 72-year-old male receiving treatment for cerebral infarction underwent an esophagogastroduodenoscopy (EGD) for suspicion of gastrointestinal bleeding. EGD revealed a type 0-I protruding lesion in the lesser curvature of the upper gastric corpus. Biopsy indicated well-differentiated adenocarcinoma. As the tumor diameter was >3 cm and the thickness of the tumor suggested submucosal invasion, laparoscopic gastrectomy was performed. Histological assessment revealed polypoid growth of an intramucosal, differentiated, tubular or papillary adenocarcinoma, with dense infiltration of lymphocytes. The carcinoma crypts were found to be EBV-positive on in situ hybridization. A review of the clinicopathological features of 25 EBV-associated GCs from 20 patients treated in our hospital between 2005 and 2014 was performed. All of these tumors, except that in the current case, appeared as shallow, depressed or ulcerative lesions. Thus, the current case appears to represent an unusual growth of EBV-positive GC.

In vivo diagnosis of early-stage gastric cancer found after Helicobacter pylori eradication using probe-based confocal laser endomicroscopy

BACKGROUND AND AIM

Early-stage gastric cancer (EGC) found after Helicobacter pylori (Hp) eradication often displays non-tumorous regenerative epithelium and/or maturated tumorous epithelium overlying the cancerous tissue, which may confuse endoscopic and histological diagnosis. Probe-based confocal laser endomicroscopy (pCLE) enables in vivo real-time optical biopsy. We compared the diagnostic yields for these EGC cases using conventional white light endoscopy (WL), magnifying endoscopy with narrow-band imaging (ME-NBI), pCLE, and endoscopic biopsy; we also compared the accuracy of the horizontal extent diagnosis between ME-NBI and pCLE.

METHODS

This study enrolled 30 patients with 36 EGC lesions after successful Hp eradication. Diagnostic yields of WL, ME-NBI, pCLE, and endoscopic biopsy were prospectively compared. Four points of cancerous margins (oral, anal, anterior, and posterior sites) were also prospectively evaluated with M-NBI and pCLE to determine the horizontal extent of the EGC.

RESULTS

Diagnostic yield was significantly higher with pCLE than with WL and endoscopic biopsy (97 vs 72%, 97 vs 72%, P = 0.0159, 0.0077, respectively), whereas it did not differ from ME-NBI (88.9%, P = 0.371). Height of non-tumorous regenerative epithelium or maturated atypical glands was 104.7 ± 34.2 μm in the pCLE-positive cases, whereas it was 188.3 ± 27.1 μm in a pCLE-negative case (P = 0.0004). Diagnostic accuracy of the horizontal margin of EGC was significantly higher with pCLE than with ME-NBI (92 vs 70%, P = 0.0159).

CONCLUSION

pCLE may be helpful for the diagnosis of ambiguous ECG found after Hp eradication because it enables real-time scanning throughout the lesion and detection of subsurface microstructure.

Mutation spectrum of TP53 gene predicts clinicopathological features and survival of gastric cancer

Background and aim

TP53 gene is frequently mutated in gastric cancer (GC), but the relationship with clinicopathological features and prognosis is conflicting. Here, we screened TP53 mutation spectrum of 214 GC patients in relation to their clinicopathological features and prognosis.

Results

TP53 nonsilent mutations were detected in 80 cases (37.4%), being frequently occurred as C:G to T:A single nucleotide transitions at 5′-CpG-3′ sites. TP53 mutations occurred more frequently in differentiated histologic type than in undifferentiated type in the early stage (48.6% vs. 7%, P=0.0006), while the mutations correlated with venous invasion among advanced stage (47.7% vs. 20.7%, P=0.04). Subset of GC with TP53 hot spot mutations (R175, G245, R248, R273, R282) presented significantly worse overall survival and recurrence free survival compared to others (both P=0.001).

Methods

Matched biopsies from GC and adjacent tissues from 214 patients were used for the experiment. All coding regions of TP53 gene (exon2 to exon11) were examined using Sanger sequencing.

Conclusion

Our data suggest that GC with TP53 mutations seems to develop as differentiated histologic type and show aggressive biological behavior such as venous invasion. Moreover, our data emphasizes the importance of discriminating TP53 hot spot mutations (R175, G245, R248, R273, R282) to predict worse overall survival and recurrence free survival of GC patients.

Association between receptor interacting serine/threonine kinase 2 polymorphisms and gastric cancer susceptibility

The present study aimed to investigate whether single nucleotide polymorphisms in receptor interacting serine/threonine kinase 2 (RIPK2), which encodes a component of the nucleotide binding oligomerization domain containing 2-RIP2 pathway, may compromise the innate immune response to Helicobacter pylori infection, leading to increased susceptibility to gastric cancer in the Japanese population. The present case control study investigated the associations between RIPK2 single nucleotide polymorphisms and gastric mucosal inflammation, atrophy and cancer susceptibility in 528 patients with gastric cancer and 697 patients without gastric malignancies on upper gastro-duodenal endoscopy. Overall, the RIPK2 rs16900627 minor allele was significantly associated with the susceptibility to gastric cancer [OR, 1.37; 95% confidence interval (CI), 1.06-1.77; P=0.016], particularly of the intestinal type (OR, 1.53; 95% CI, 1.13-2.07; P=0.0062). It was also significantly associated with gastric mucosal atrophy (OR, 1.83; 95% CI, 1.14-2.93; P=0.011). When assessing the severity of chronic gastritis using the updated Sydney system, the activity and inflammation scores, as well as atrophy and metaplasia scores, were significantly higher in rs16900627 minor allele carriers compared with wild-type homozygotes. In patients younger than 60 years old, the pepsinogen I/II ratio was significantly lower in rs16900627 minor allele carriers compared with wild-type homozygotes (P=0.037). The rs16900627 minor allele is associated with the severity of gastric mucosal inflammation and the development of gastric mucosal atrophy. Carriers of this allele may have an increased risk for the development of gastric cancer, particularly of the intestinal type.

Demonstration of potential link between Helicobacter pylori related promoter CpG island methylation and telomere shortening in human gastric mucosa

BACKGROUND

Telomere length shortening in Helicobacter pylori (H. pylori) infected gastric mucosa constitutes the earliest steps toward neoplastic transformation. In addition to this genotoxic changes, epigenetic changes such as promoter CpG island (PCGI) methylation are frequently occurred in H. pylori infected gastric mucosa. The aim of this study was to investigate a potential link between H. pylori related PCGI methylation and telomere length shortening in the human gastric mucosa.

METHODS

Telomere length was measured in non-neoplastic gastric mucosa from 106 cancer-free subjects. To identify H. pylori related PCGI methylation, bisulfite pyrosequencing was used to quantify the methylation of 49 PCGIs from 47 genes and LINE1 repetitive elementResults: We identified five PCGIs (IGF2, SLC16A12, SOX11, P2RX7 and MYOD1), which the methylation is closely associated with H. pylori infection. Hypermethylation of all these PCGIs was associated with development of pathological state from normal to mild, active, and atrophic gastritis (P<0.001) and lower pepsinogen I/II ratio (P<0.05), an indicator for gastric mucosal atrophy. Telomere shortening was significantly associated with mean Z score methylation of five PCGIs (R=-0.39, P<0.0001) and four of these locus (IGF2: R=-0.35, P=0.0003, SLC16A12: R=-0.35, P=0.0002, P2RX7: R=-0.29, P=0.003, and MYOD1: R=-0.33, P=0.0005). Multivariate analysis revealed that telomere shortening held an increased risk for hypermethylation (odds ratio: 1.71, 95% confidence interval: 1.11-2.63, P=0.016).

CONCLUSION

Potential link between H. pylori related PCGI methylation and telomere shortening emphasize the importance of genotoxic-epigenetic interaction in the pathological state of H. pylori infected gastric mucosa.

A Comparative Study of White Light Endoscopy, Chromoendoscopy and Magnifying Endoscopy with Narrow Band Imaging in the Diagnosis of Early Gastric Cancer after Helicobacter pylori Eradication

Background & Aim: Early-stage gastric cancer (EGC) found after H. pylori eradication often has non-tumorous epithelium on the tumorous tissue and/or surface differentiation of tumors, which may confuse endoscopic and histologic diagnosis. We investigated the diagnostic reliability of EGC using conventional white light endoscopy (WLE), chromoendoscopy (CE) using indigo carmine, and magnifying endoscopy with narrow band imaging (ME-NBI) in patients with EGC with or without history of prior H. pylori eradication therapy.Methods: Diagnostic reliability of EGC by using the WLE, CE and ME-NBI was investigated in 71 EGC lesions diagnosed after successful H. pylori eradication (eradication group) and 115 EGC lesions with current H. pylori infection (control group).Results: Diagnostic reliability of EGC was lower in the eradication group than in the control group using all three modalities. In particular, the diagnostic accuracy of CE in the eradication group was especially lower compared to that of the control group (WLE: 74.6% vs. 86.1%, P=0.05; CE: 64.8% vs. 91.3%, P<0.0001; ME-NBI: 88.7% vs. 98.2%, P=0.01). The ME-NBI scored better in comparison with WLE and CE in the eradication group (both P<0.05). The indistinct EGC lesions in the eradicated group by using CE were associated with the presence of histological changes such as non-tumorous epithelium on the tumor and/or surface differentiation of tumors (P=0.005).Conclusions: It should be noted that the diagnostic reliability of EGC after H. pylori eradication becomes lower especially using CE. Indistinguishable cases using CE are associated with histological findings such as non-tumorous epithelium on the tumor and/or surface differentiation of tumors.Abbreviations: CE: chromoendoscopy; EGD: esophagogastroduodenoscopy; EGC: Early-stage gastric cancer; ESD: endoscopic submucosal dissection; H. pylori: Helicobacter pylori; ME-NBI: magnifying endoscopy with narrow band imaging; WLE: white light endoscopy.

Genetic polymorphisms of MAFK, encoding a small Maf protein, are associated with susceptibility to ulcerative colitis in Japan

AIM

To investigate whether single nucleotide polymorphisms in maf protein K (MAFK), which encodes the MAFK, lead to increased susceptibility to ulcerative colitis in the Japanese population.

METHODS

This case control study examined the associations between MAFK single nucleotide polymorphisms (rs4268033 G>A, rs3735656 T>C and rs10226620 C>T) and ulcerative colitis susceptibility in 174 patients with ulcerative colitis (UC) cases, and 748 subjects without no lower abdominal symptoms, diarrhea or hematochezia (controls). In addition, as the second controls, we set 360 subjects, who have an irregular bowel movement without abnormal lower endoscopic findings (IBM controls).

RESULTS

The genotype frequency of rs4268033 AA and allelic frequency of the rs4268033A allele were significantly higher in the UC cases than in both controls (P = 0.0005 and < 0.0001, P = 0.015 and 0.0027 vs controls and IBM controls, respectively). Logistic regression analysis after adjustment for age and gender showed that the rs4268033 AA and rs3735656 CC genotypes were significantly associated with susceptibility to UC development (OR = 2.63, 95%CI: 1.61-4.30, P = 0.0001 and OR = 1.81; 95%CI: 1.12-2.94, P = 0.015, respectively). Similar findings were observed by the comparison with IBM controls. In addition, the rs4268033 AA genotype was significantly associated with all phenotypes of UC except early onset. There was no significant association between rs10226620 and ulcerative colitis.

CONCLUSION

Our results provide the first evidence that MAFK genetic polymorphisms are significantly associated with susceptibility to UC development. In particular, rs4268033 is closely associated with an increased risk for the development of UC.

Endoscopic features of lymphoid follicles using blue laser imaging (BLI) endoscopy in the colorectum and its association with chronic bowel symptoms

Background/Aim

In the colorectum, lymphoid follicles hyperplasia (LH) is sometimes observed as small, round, yellowish-white nodules. The novel image-enhanced endoscopy system named blue laser imaging (BLI) provides enhanced the contrast of surface vessels using lasers for light illumination. We investigated the endoscopic features of LH observed by using BLI endoscopy and its association with chronic bowel symptoms.

Patients/Methods

300 participants undergoing colonoscopy for various indications were enrolled. Entire colorectum was observed by using BLI-bright mode with non-magnification view. LH was defined as well demarcated white nodules. Elevated LH with erythema was distinguished as LH severe.

Results

LHs were observed more clearly by using BLI-bright mode compared to conventional white light colonoscopy and were also histologically confirmed as intense infiltration of lymphocytes or plasmacytes. LH was observed in 134 subjects (44.6%) and 67 (22.3%) were LH severe. LH was associated younger age (Odds ratio (OR) = 1.05, 95%Confidence Interval (95%CI) = 1.03–1.07, P<0.0001) and chronic bowel symptoms including constipation, hard stools, diarrhea and loose stools (all LH: OR = 4.03, 95%CI = 2.36–6.89, P<0.0001, LH severe: OR = 5.31, 95%CI = 2.64–10.71, P<0.0001). LH severe was closely associated with both constipation associated symptoms (OR = 3.94, 95%CI = 1.79–8.66, P = 0.0007) and diarrhea associated symptoms (OR = 5.22, 95%CI = 2.09–13.05, P = 0.0004). In particular, LH severe in the ascending colon was strongly associated with bowel symptoms (P<0.0001).

Conclusion

LH, visualized by using BLI endoscopy was associated with bowel symptom, raising the possibility of pathogenic role of this endoscopic finding in the functional lower gastrointestinal disorders.

Usefulness of confocal laser endomicroscopy to diagnose ulcerative colitis-associated neoplasia

Chromoendoscopy, narrow-band imaging (NBI), and confocal laser endomicroscopy (CLE) have been introduced in ulcerative colitis (UC)-associated neoplasia surveillance. We aimed to determine the ability of CLE to differentiate among UC-associated neoplasia (differentiated type or undifferentiated type), sporadic adenoma, and circumscribed regenerative lesions. Of 665 patients with UC, we carried out probe-based CLE (pCLE) on 12 patients with suspected UC-associated neoplasia in addition to magnifying chromoendoscopy with crystal violet and NBI. We compared pCLE findings with pathological diagnoses. pCLE could differentiate UC-associated differentiated cancer from other pathologies such as solitary adenoma and non-neoplastic circumscribed regenerative lesions on the basis of back-to-back orientation of crypts (P = 0.048), and UC-associated undifferentiated cancer from other pathologies on the basis of dark trabecular architecture (P = 0.015). Sensitivity, specificity, and accuracy of combination of back-to-back orientation of crypts and dark trabecular architecture for carcinoma or dysplasia were 100%, 83%, and 92%, respectively. In vivo microscopic observation with pCLE was helpful to evaluate the suspected UC-associated neoplasia.

Morphologic characterization of residual DNA methylation in the gastric mucosa after Helicobacter pylori eradication

Residual DNA methylation in the gastric mucosa after Helicobacter pylori (H. pylori) eradication may have a role in gastric carcinogenesis. We examined the association between morphologic features and promoter methylation status of non-neoplastic gastric mucosa especially after H. pylori eradication. A total of 140 gastric specimens from 99 participants who had at least 6 months of post-eradication period were examined. The magnifying narrow-band imaging (NBI) endoscopic feature of gastric mucosa was divided into two types: restored-small, round pits, accompanied with honeycomb-like subepithelial capillary networks; atrophic-well-demarcated oval or tubulovillous pits with clearly visible coiled or wavy vessels. Methylation status of five candidate genes (MYOD1, SLC16A12, IGF2, RORA, and PRDM5) were examined by bisulfite pyrosequencing. The atrophic type, informative endoscopic features of intestinal metaplasia, demonstrated higher methylation levels in all five genes compared to the restored type (all P < 0.0001). In the restored type, methylation levels were significantly lower among the samples with longer post-eradication period (for all genes, P < 0.0001), which was not observed in atrophic type (for all genes, P > 0.1). Multivariate analysis demonstrated that atrophic type or presence of intestinal held an independent factor for hyper methylation (odds ratio: 24.69, 95% confidence interval: 6.95-87.76, P < 0.0001). The atrophic type by the magnifying NBI and presence of intestinal metaplasia are the morphologic characteristics of residual DNA methylation of after H. pylori eradication, regardless of the post-eradication period and it might be considered as the epigenetic irreversible point with H. pylori eradication.

In vivo characterization of abnormalities in small-bowel diseases using probe-based confocal laser endomicroscopy

BACKGROUND AND STUDY AIMS

 Probe-based confocal laser endomicroscopy (pCLE) enables real-time optical biopsy. Little is known about pCLE imaging deep inside the small bowel, therefore the aim of this study was to determine its usefulness.

PATIENTS AND METHODS

 Between April 2014 and January 2016, we performed 38 pCLE examinations during double-balloon enteroscopy with intravenous fluorescein in 37 patients with: tumors (n = 10), vascular disorders (n = 6), inflammatory diseases and drug injuries (n = 13), other disorders (n = 4), and normal findings (n = 4). We measured the calibers of capillary and lymphatic vessels at 15 different sites and compared the calibers between pCLE images and histopathology. We also compared pCLE findings with pathologic diagnosis.

RESULTS

 The inner diameters of capillary vessels beneath the epithelium and in the middle of villi were 16.2 ± 3.0 µm and 14.5 ± 3.1 µm, respectively, in the pCLE images, but these were not consistent with formalin-fixed paraffin-embedded histology. In tumors, larger capillary vessels were observed in aggressive malignant lymphoma and metastasis, and a "soccer ball-like pattern" constituting homogenous dark cells packed with polygonal, narrower capillary vessels was characteristic in pCLE images of a malignant lymphoma follicle. Hereditary hemorrhagic telangiectasia and angiodysplasia contained anastomosis of capillary vessels of different calibers. In IgA vasculitis, segmental capillary strictures were observed. Intestinal lymphangiectasia with protein-losing enteropathy contained a reticular network of lymphatic vessels and dilated lymphatic ducts accompanied by numerous cell gaps. pCLE findings corresponded to pathologic diagnosis in 32 examinations (91 %).

CONCLUSIONS

 pCLE is useful for in vivo analysis of abnormalities of the capillary and lymphatic vessels and epithelium, and for diagnosis in various small-bowel diseases.

Potential link between Fusobacterium enrichment and DNA methylation accumulation in the inflammatory colonic mucosa in ulcerative colitis

BACKGROUND AND AIM

Fusobacterium enrichment has been associated with colorectal cancer development. Ulcerative colitis (UC) associated tumorigenesis is characterized as high degree of methylation accumulation through continuous colonic inflammation. The aim of this study was to investigate a potential link between Fusobacterium enrichment and DNA methylation accumulation in the inflammatory colonic mucosa in UC.

METHODS

In the candidate analysis, inflamed colonic mucosa from 86 UC patients were characterized the methylation status of colorectal a panel of cancer related 24 genes. In the genome-wide analysis, an Infinium HumanMethylation450 BeadChip array was utilized to characterize the methylation status of >450,000 CpG sites for fourteen UC patients. Results were correlated with Fusobacterium status.

RESULTS

UC with Fusobacterium enrichment (FB-high) was characterized as high degree of type C (for cancer-specific) methylation compared to other (FB-low/neg) samples (P<0.01). Genes hypermethylated in FB-high samples included well-known type C genes in colorectal cancer, such as MINT2 and 31, P16 and NEUROG1. Multivariate analysis demonstrated that the FB high status held an increased likelihood for methylation high as an independent factor (odds ratio: 16.18, 95% confidence interval: 1.94-135.2, P=0.01). Genome-wide methylation analysis demonstrated a unique methylome signature of FB-high cases irrespective of promoter, outside promoter, CpG and non-CpG sites. Group of promoter CpG sites that were exclusively hypermethylated in FB-high cases significantly codified the genes related to the catalytic activity (P=0.039).

CONCLUSION

Our findings suggest that Fusobacterium accelerates DNA methylation in specific groups of genes in the inflammatory colonic mucosa in UC.

Histological evaluations of primary lesions are independently associated with prognosis in patients with gastric cancer who receive neoadjuvant chemotherapy

Neoadjuvant chemotherapy may improve outcomes for patients with locally advanced gastric cancer (GC). To explore useful predictive factors for the response of advanced GC to neoadjuvant chemotherapy, tumor responses were assessed using computed tomography (CT) with histological based criteria. A total of 78 patients with advanced GC undergoing neoadjuvant chemotherapy were included. CT-based response assessment was performed following 2 courses of treatment. Histological evaluation of resected specimens was also performed according to the Japanese classification of gastric carcinoma. Grade 1b, 2 and 3 (viable tumor cells remaining in <2/3 of the tumorous area) were defined as histological responders. The results were associated with overall survival (OS) and progression-free survival (PFS). The majority of the cases underwent tegafur/gimeracil/oteracil based preoperative chemotherapy as the first line of treatment (n=76, 96%). A total of 25 (32%) and 29 (37%) cases were considered to be CT and histological responders, respectively. CT-based evaluation was not associated with OS or PFS, while histological evaluation was significantly associated with OS and PFS. Histological based evaluation was not associated with CT and GI X-ray or endoscopy-based evaluation of primary lesions. Multivariate survival analysis using Cox's regression model demonstrated that histological non-response was an independent prognostic factor for predicting worse OS. Histological-based evaluation of primary lesions was independently associated with prognosis in patients with GC who underwent neoadjuvant chemotherapy.

Magnifying narrow-band imaging of gastric mucosal morphology predicts the H. pylori-related epigenetic field defect

DNA methylation is associated with "field defect" in the gastric mucosa. To characterize "field defect" morphologically, we examined DNA methylation of non-neoplastic gastric mucosa in relation to their morphology seen by narrow-band imaging (NBI) with magnifying endoscopy. Magnifying NBI of non-neoplastic gastric body was classified as follows: normal-small and round pits with uniform subepithelial capillary networks; type 1-a little enlarged round pits with indistinct subepithelial capillary networks; type 2-remarkably enlarged pits with irregular vessels; and type 3-clearly demarcated oval or tubulovillous pits with bulky coiled or wavy vessels. Methylation of nine candidate genes (MYOD1, SLC16A12, GDNF, IGF2, MIR 124A1, CDH1, PRDM5, RORA and MLF1) were determined by bisulfite pyrosequencing. Infinium HumanMethylation450 array was used to characterize the methylation of >450,000 CpG sites. Mean Z score methylation of nine genes positively correlated with the changes of mucosal patterns from normal to types 1, 2, and 3 (P < 0.0001). Genome-wide analysis showed that development of mucosal patterns correlated with methylation accumulation especially at CpG islands. Genes with promoter CpG islands that were gradually methylated with the development of mucosal patterns significantly enriched the genes involved in zinc-related pathways. The results indicates that gastric mucosal morphology predicts a "field defect" in this tissue type. Accumulation of DNA methylation is associated with "field defect" in the non-neoplastic gastric mucosa. Endoscopic identification of "field defect" has important implications for preventing gastric cancer. Our results suggest that magnifying NBI of gastric mucosal morphology predicts a "field defect" in the gastric mucosa.