Premalignant conditions of gastric cancer

A Study on the Glucose Breath Test Positivity Rate and Occurrence of Small Intestine Bacterial Overgrowth-Related Symptoms Caused by Long-Term Use of Proton Pump Inhibitor (PPI) Versus Potassium-Competitive Acid Blocker (P-CAB) in Elderly Patients: SIBO Between PPI and P-CAB

Background/Aims: Long-term acid suppression with proton pump inhibitors (PPI) leads to hypochlorhydria and facilitates the growth of bacterial flora in the small intestine. Novel acid-suppressants called potassium-competitive acid blockers (P-CABs) seem to be superior to PPIs. However, data on the risk of small intestinal bacterial overgrowth (SIBO) in patients taking P-CABs are limited. Method: We retrospectively analyzed a consecutive series of patients with long-term acid-suppressant (PPIs or P-CABs) use for gastroesophageal reflux disease or nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy. All of them underwent endoscopic examinations and Helicobacter pylori testing and took PPIs or P-CABs for at least 3 months. Glucose hydrogen breath tests (GBT) were performed to check for SIBO, and newly developed SIBO-related symptoms including bloating, postprandial discomfort, diarrheas, and constipation, were evaluated. Results: A total of 142 patients were enrolled. Six patients were excluded due to equivocal Helicobacter pylori infection results. The frequency of positive GBTs was 31.7% (25/79) for PPI and 22.8% (13/57) for P-CAB use (p=0.15). Regarding GBT positivity, age-related factor was found to be significant in multivariate analysis (p=0.02). The results of multivariate analysis in cases of SIBO-related symptoms showed that GBT positivity and PPI use were significant (p < 0.01). Conclusion: Long-term use of gastric acid suppressants resulted in positive GBT in approximately 30% of patients, and the risk was particularly high in elderly patients. The occurrence of SIBO-related symptoms was significant in long-term use of PPIs and in patients with positive GBT.

Gastric Intestinal Metaplasia: Real Culprit or Innocent Bystander as a Precancerous Condition for Gastric Cancer?

Gastric intestinal metaplasia (GIM), which denotes conversion of gastric mucosa into an intestinal phenotype, can occur in all regions of the stomach, including cardiac, fundic, and pyloric mucosa. Since the earliest description of GIM, its association with gastric cancer of the differentiated (intestinal) type has been a well-recognized concern. Many epidemiologic studies have confirmed GIM to be significantly associated with subsequent gastric cancer development. Helicobacter pylori, the principal etiologic factor for gastric cancer, plays the most important role in predisposing to GIM. Although the role of GIM in the stepwise progression model of gastric carcinogenesis (the so-called "Correa cascade") has come into question recently, we review the scientific evidence that strongly supports this long-standing model and propose a new progression model that builds on the Correa cascade. Eradication of H pylori is the most important method for preventing gastric cancer globally, but the effect of eradication on established GIM, is limited, if any. Endoscopic surveillance for GIM may, therefore, be necessary, especially when there is extensive corpus GIM. Recent advances in image-enhanced endoscopy with integrated artificial intelligence have facilitated the identification of GIM and neoplastic lesions, which will impact preventive strategies in the near future.

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

Characteristics of gastric precancerous conditions and Helicobacter pylori infection among dyspeptic patients in north-eastern Iran: is endoscopic biopsy and histopathological assessment necessary?

Background

Early detection and appropriate treatment of precancerous, mucosal changes could significantly decrease the prevalence of life-threatening gastric cancer. Biopsy of the normal-appearing mucosa to detect Helicobacter pylori and these conditions is not routinely obtained. This study assesses the prevalence and characteristics of H. pylori infection and precancerous conditions in a group of patients suffering from chronic dyspepsia who were subjected to gastric endoscopy and biopsy mapping.

Methods

This cross-sectional study included dyspeptic patients, not previously treated for H. pylori, undergoing esophagogastroduodenoscopy (EGD) with their gastric endoscopic biopsies obtained for examination for evidence of H. pylori infection and precancerous conditions. Demographic and clinical data on the gender, smoking, opium addiction, alcohol consumption, medication with aspirin, corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs) and family history of cancer were collected by interviewing the patients and evaluating their health records. The cohort examined consisted of 585 patients with a mean (SD) age of 48.0 (14.46) years, 397 (67.9%) of whom were women.

Results

H. pylori infection was identified in 469 patients (80.2%) with the highest prevalence (84.2%) in those aged 40–60 years. Opium addiction correlated with a higher a H. pylori infection rate, while alcohol consumption was associated with a lower rate by Odds Ratio 1.98 (95% CI 1.11–3.52) and 0.49 (95% CI 0.26–0.92), respectively. The prevalence of intestinal metaplasia, gastric atrophy and gastric dysplasia was 15.2, 12.6 and 7.9%, respectively. Increased age, positive H. pylori infection, endoscopic abnormal findings and opium addiction showed a statistically significant association with all precancerous conditions, while NSAID consumption was negatively associated with precancerous conditions. For 121 patients (20.7% of all), the EGD examination revealed normal gastric mucosa, however, for more than half (68/121, 56.2%) of these patients, the histological evaluation showed H. pylori infection, and also signs of atrophic mucosa, intestinal metaplasia and dysplasia in 1.7, 4.1 and 1.7%, respectively.

Conclusion

EGD with gastric biopsy mapping should be performed even in the presence of normal-appearing mucosa, especially in dyspeptic patients older than 40 years with opium addiction in north-eastern Iran. Owing to the high prevalence of precancerous conditions and H. pylori infection among patients with dyspepsia in parts of Iran, large-scale national screening in this country should be beneficial.

Helicobacter pylori-Induced Inflammation: Possible Factors Modulating the Risk of Gastric Cancer

Chronic inflammation and long-term tissue injury are related to many malignancies, including gastric cancer (GC). Helicobacter pylori (H. pylori), classified as a class I carcinogen, induces chronic superficial gastritis followed by gastric carcinogenesis. Despite a high prevalence of H. pylori infection, only about 1–3% of people infected with this bacterium develop GC worldwide. Furthermore, the development of chronic gastritis in some, but not all, H. pylori-infected subjects remains unexplained. These conflicting findings indicate that clinical outcomes of aggressive inflammation (atrophic gastritis) to gastric carcinogenesis are influenced by several other factors (in addition to H. pylori infection), such as gut microbiota, co-existence of intestinal helminths, dietary habits, and host genetic factors. This review has five goals: (1) to assess our current understanding of the process of H. pylori-triggered inflammation and gastric precursor lesions; (2) to present a hypothesis on risk modulation by the gut microbiota and infestation with intestinal helminths; (3) to identify the dietary behavior of the people at risk of GC; (4) to check the inflammation-related genetic polymorphisms and role of exosomes together with other factors as initiators of precancerous lesions and gastric carcinoma; and (5) finally, to conclude and suggest a new direction for future research.

Gastric cancer in patients with gastric atrophy and intestinal metaplasia: A systematic review and meta-analysis

AIM

Intestinal metaplasia (IM) and gastric atrophy (GA) are precancerous lesions in the stomach. There is a large debate on natural course of these lesions and surveillance strategy in these patients. This meta-analysis was aimed to find the most appropriate follow up and the rate of progression from IM and GA to GC.

METHODS

This meta-analysis is followed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases including EMBASE, PubMed, Web of Science databases, Scopus, and the Cochrane Library were searched until July 2018. Cochran's Q test and I-square (I2) test were used to examine heterogeneity across included studies. We pooled data using random-effect or fixed effect models indicated as incidence rate or proportion with 95% confidence intervals (CI). The variables of study included demographic data, endoscopy interval, follow up interval and time, GA and IM type and GC stage. Moreover, incidence rate of GC and progress rate, regress and persistence proportion in both GA and IM patients were assessed.

RESULTS

Overall, 68 original articles out of 32981 citations were included in our meta-analysis. The pooled GC incidence rate in patients with GA was 1.24 (95% CI, 0.80, 1.76; I2: 83.6%) cases per 1,000 person-years. The rates of later diagnosis of IM and gastric dysplasia in patients with GA were estimated as 41.42 (95% CI, 3.11, 64.45; I2: 95.6%) and 6.23 (95% CI, 2.34, 11.46; I2: 83.0%) cases per 1,000 person-years, respectively. The pooled regressed proportion was 32.23 (95% CI, 18.07-48.02; I2: 94.0%) and the persistence proportion was 38.83 (95% CI, 20.20-59.13; I2: 97.0%) per 100 observations in GA patients. In IM studies, the pooled incidence rate of GC was 3.38 (95% CI, 2.13, 4.85; I2: 93.4%) cases per 1,000 person-years. The progressed rate to dysplasia in IM patient was estimated to be 12.51 (95% CI, 5.45, 22.03; I2: 95.1%) cases per 1,000 person-years. The pooled regressed proportion was 31.83 (95% CI, 25.48-38.51; I2: 91.0%) and the persistence proportion was 43.46 (95% CI, 32.52-54.71; I2: 96.0%) per 100 observations in IM patients.

CONCLUSION

Overall, the incidence of GC in patients with IM and GA are low but there is heterogeneity in data with the highest rate in Asian, males with those with incomplete IM. There is probability of regression or persistence without progression in patients with IM and GA who receive appropriate management.

Performance of a Multiplex Serological Helicobacter pylori Assay on a Novel Microfluidic Assay Platform

Infection with Helicobacter pylori (H. pylori) occurs in 50% of the world population, and is associated with the development of ulcer and gastric cancer. Serological diagnostic tests indicate an H. pylori infection by detecting antibodies directed against H. pylori proteins. In addition to line blots, multiplex assay platforms provide smart solutions for the simultaneous analysis of antibody responses towards several H. pylori proteins. We used seven H. pylori proteins (FliD, gGT, GroEL, HpaA, CagA, VacA, and HP0231) and an H. pylori lysate for the development of a multiplex serological assay on a novel microfluidic platform. The reaction limited binding regime in the microfluidic channels allows for a short incubation time of 35 min. The developed assay showed very high sensitivity (99%) and specificity (100%). Besides sensitivity and specificity, the technical validation (intra-assay CV = 3.7 ± 1.2% and inter-assay CV = 5.5 ± 1.2%) demonstrates that our assay is also a robust tool for the analysis of the H. pylori-specific antibody response. The integration of the virulence factors CagA and VacA allow for the assessment of the risk for gastric cancer development. The short assay time and the performance of the platform shows the potential for implementation of such assays in a clinical setting.

Immunotherapeutic Strategies for Gastric Carcinoma: A Review of Preclinical and Clinical Recent Development

Gastric carcinoma (GC) is the 2nd most common cause of cancer-related death. Despite advances in conventional treatment and surgical interventions, a high percentage of GC patients still have poor survival. Recently, immunotherapy has become a promising approach to treat GC. Here, we present preclinical and clinical studies encouraging the use of vaccination, adoptive T-cell therapy (ACT), and immune checkpoint inhibitors, such as programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). The ongoing immunotherapy clinical trials have shown promising results in safety and tolerability even in late-stage GC patients. Moreover, we highlight that the combination of ACT with chemotherapy could be the best choice to treat GC.

Gastrointestinal system involvement in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystem disorder which can affect the gastrointestinal (GI) system. Although GI symptoms can manifest in 50% of patients with SLE, these have barely been reviewed due to difficulty in identifying different causes. This study aims to clarify clinical characteristics, diagnosis and treatment of the four major SLE-related GI system complications: protein-losing enteropathy (PLE), intestinal pseudo-obstruction (IPO), hepatic involvement and pancreatitis. It is a systematic review using MEDLINE and EMBASE databases and the major search terms were SLE, PLE, IPO, hepatitis and pancreatitis. A total of 125 articles were chosen for our study. SLE-related PLE was characterized by edema and hypoalbuminemia, with Technetium 99m labeled human albumin scintigraphy (^99mTc HAS) and alpha-1-antitrypsin fecal clearance test commonly used as diagnostic test. The most common site of protein leakage was the small intestine and the least common site was the stomach. More than half of SLE-related IPO patients had ureterohydronephrosis, and sometimes they manifested as interstitial cystitis and hepatobiliary dilatation. Lupus hepatitis and SLE accompanied by autoimmune hepatitis (SLE-AIH overlap) shared similar clinical manifestations but had different autoantibodies and histopathological features, and positive anti-ribosome P antibody highly indicated the diagnosis of lupus hepatitis. Lupus pancreatitis was usually accompanied by high SLE activity with a relatively high mortality rate. Early diagnosis and timely intervention were crucial, and administration of corticosteroids and immunosuppressants was effective for most of the patients.

Helicobacter pylori Eradication Reduces the Metachronous Recurrence of Gastric Neoplasms by Attenuating the Precancerous Process

PURPOSE

The importance of Helicobacter pylori eradication after endoscopic resection (ER) of gastric neoplasms remains controversial. In this study, we clarified the importance of H. pylori eradication for metachronous lesions after ER.

MATERIALS AND METHODS

This study included 3,882 patients with gastric neoplasms who underwent ER. We included patients infected with H. pylori who received eradication therapy. Among them, 34 patients with metachronous lesions after ER and 102 age- and sex-matched patients (nonmetachronous group) were enrolled. Background mucosal pathologies such as atrophy and intestinal metaplasia (IM) were evaluated endoscopically. The expression levels of CDX1, CDX2, Sonic hedgehog (SHH), and SOX2 were evaluated based on H. pylori eradication and the development of metachronous lesions.

RESULTS

The eradication failure rate was higher in the metachronous group than in the nonmetachronous group (P=0.036). Open-type atrophy (P=0.003) and moderate-to-severe IM (P=0.001) occurred more frequently in the metachronous group. In patients with an initial diagnosis of dysplasia, the eradication failure rate was higher in the metachronous group than in the nonmetachronous group (P=0.002). In addition, open-type atrophy was more frequent in the metachronous group (P=0.047). In patients with an initial diagnosis of carcinoma, moderate-to-severe IM occurred more frequently in the metachronous group (P=0.003); however, the eradication failure rate was not significantly different between the two groups. SHH and SOX2 expression was increased, and CDX2 expression was decreased in the nonmetachronous group after eradication (P<0.05).

CONCLUSIONS

Open-type atrophy, moderate-to-severe IM, and H. pylori eradication failure were significantly associated with metachronous lesions. However, eradication failure was significantly associated with dysplasia, but not carcinoma, in the metachronous group. Thus, H. pylori eradication may play an important role in preventing metachronous lesions after ER for precancerous lesions before carcinomatous transformation.

Safety of proton pump inhibitors and risk of gastric cancers: review of literature and pathophysiological mechanisms

INTRODUCTION

Despite being an overall safe drug, several long-term adverse effects are associated with proton pump inhibitors (PPIs). The link between PPI use and gastric neuroendocrine tumors (NETs), gastric adenocarcinomas and Barrett's esophagus progression gastric cancers has been investigated due to PPI-induced hypergastrinemia.

AREAS COVERED

The pathophysiological mechanisms underlying PPI exposure and gastric NETs, gastric adenocarcinomas and Barrett's esophagus progression are discussed. The quality of randomized control studies, cohort studies and case reports investigating the link between gastric cancers and PPIs are examined. Recommendations for clinicians are provided.

EXPERT OPINION

PPIs cause a hypergastrinemic state, increasing enterochromaffin-like cell dysplasia and risk of gastric NET development, increasing gastritis severity in the context of Helicobacter pylori infection, and progression of carcinogenesis in a certain predisposed subset of Barrett's esophagus patients. There are case reports of PPI-induced gastric NETs and adenocarcinomas as consequences of these effects. In pernicious anemia and chronic gastritis, clinicians should be aware of potential increased risk of gastric NET development with chronic PPI use in these patients. Eradication status of H. pylori prior to commencing long-term PPI therapy should be established to reduce the risk of severe atrophic gastritis and development of gastric dysplasia.

Helicobacter pylori Eradication Prevents Metachronous Gastric Neoplasms after Endoscopic Resection of Gastric Dysplasia

PURPOSE

There is insufficient data about the role of eradication of H. pylori after endoscopic resection (ER) for gastric dysplasia. The aim was to investigate the benefit of H. pylori eradication after ER in patients with gastric dysplasia to prevent metachronous gastric neoplasms.

MATERIALS AND METHODS

We retrospectively reviewed 1872 patients who underwent ER of gastric dysplasia. We excluded patients with a follow-up period of <2 years or who had not undergone tests for active H. pylori infection. A total of 282 patients were enrolled. The patients were categorized into those without active H. pylori infection (H. pylori-negative group, n = 124), those who successfully underwent H. pylori eradication (eradicated group, n = 122), and those who failed or did not undergo H. pylori eradication (persistent group, n = 36).

RESULTS

Metachronous recurrence was diagnosed in 36 patients, including 19 in the H. pylori-negative group, 10 in the eradicated group, and 7 in the persistent group. The cumulative incidence of metachronous recurrence was significantly lower in the H. pylori-eradicated group in comparison with either of the H. pylori-persistent (non-eradicated or failed) groups (p = 0.039). Similarly, the incidence of metachronous recurrence was significantly lower in the H. pylori-eradicated group compared with the H. pylori-negative group (p = 0.041).

CONCLUSION

Successful H. pylori eradication may reduce the development of metachronous gastric neoplasms after ER in patients with gastric dysplasia.

The stomach in health and disease

The stomach is traditionally regarded as a hollow muscular sac that initiates the second phase of digestion. Yet this simple view ignores the fact that it is the most sophisticated endocrine organ with unique physiology, biochemistry, immunology and microbiology. All ingested materials, including our nutrition, have to negotiate this organ first, and as such, the stomach is arguably the most important segment within the GI tract. The unique biological function of gastric acid secretion not only initiates the digestive process but also acts as a first line of defence against food-borne microbes. Normal gastric physiology and morphology may be disrupted by Helicobacter pylori infection, the most common chronic bacterial infection in the world and the aetiological agent for most peptic ulcers and gastric cancer. In this state-of-the-art review, the most relevant new aspects of the stomach in health and disease are addressed. Topics include gastric physiology and the role of gastric dysmotility in dyspepsia and gastroparesis; the stomach in appetite control and obesity; there is an update on the immunology of the stomach and the emerging field of the gastric microbiome. H. pylori-induced gastritis and its associated diseases including peptic ulcers and gastric cancer are addressed together with advances in diagnosis. The conclusions provide a future approach to gastric diseases underpinned by the concept that a healthy stomach is the gateway to a healthy and balanced host. This philosophy should reinforce any public health efforts designed to eradicate major gastric diseases, including stomach cancer.

Association between pro-(IL-8) and anti-inflammatory (IL-10) cytokine variants and their serum levels and H. pylori-related gastric carcinogenesis in northern India

BACKGROUND

Interleukin (IL)-8 -251 T/A and IL-10 (-1082 G/A and -819/592 C/T) polymorphisms and their expression may influence gastritis, atrophy, intestinal metaplasia (IM) and gastric cancer (GC) following H. pylori infection.

METHODS

Genotyping of these genes was performed (ASO-PCR) in 200, 182 and 250 with GC, functional dyspepsia (FD) and healthy controls (HC), respectively. Anti-H. pylori IgG-antibody was tested in all and serums IL-8 and IL-10 were measured randomly in 60 subjects of each group by ELISA.

RESULTS

Pro-(IL-8)-251 AA and anti-inflammatory (IL-10)-819 TT genotypes were commoner among GC than HC (p = 0.023, OR 1.86 [1.09-3.2] and p = 0.020, OR 2.0 [1.11-3.5]) but comparable with FD. IL-8 AA and IL-10-819 T allele carriage was also commoner in H. pylori-infected GC than HC (p = 0.011, OR 2.47 [1.23-5.0], and p = 0.018, OR 2.3 (1.16-4.59). IL-10-1082 G/A genotype and haplotypes (ACC, GCC, ATA and GTA) were comparable in all groups. Circulating levels of IL-8 and IL-10 were higher among GC than HC but comparable to FD (IL-8; 57.64 [6.44-319.46] vs. 54.35 [4.24-318.96] and 26.33 [4.67-304.54] pg/ml, p < 0.001 and IL-10; 15.47 [1.01-270.87] vs. 12.28 [0.96-64.88] and 3.79 [1.24-56.65], p < 0.001 for GC vs. HC). IL-8/IL-10 ratio was lower among GC than HC but higher than FD (3.7 [0.18-38.41] vs. 6.59 [0.98-130.2], p < 0.001 and 4.22 [0.15-61.4], p < 0.01). Circulating levels of IL-8, IL-10 and IL-8/lL-10 ratios were different among H. pylori-infected and non-infected GC than HC (p < 0.001, p < 0.001 and p < 0.01).

CONCLUSIONS

Pro-(IL-8)-251 T/A and anti-inflammatory (IL-10)-819 C/T gene polymorphisms and their circulating levels may play a role in H. pylori-associated gastric carcinogenesis in northern India.

AKT plays a crucial role in gastric cancer

The AKT protein is involved in the phosphatidylinositol-3 kinase signaling pathway and is a vital regulator of survival, proliferation and differentiation in various types of cells. Helicobacter pylori infection induces epithelial cell proliferation and oxidative stress in chronic gastritis. These alterations lead to telomere shortening, resulting in the activation of telomerase. AKT, in particular, is activated by H. pylori-induced inflammation. AKT then promotes the expression of human telomerase reverse transcriptase, which encodes a catalytic subunit of telomerase, and induces telomerase activity, an essential component of the process of carcinogenesis. AKT activation is increased in gastric mucosa with carcinogenic properties and is associated with the low survival of patients with gastric cancer. The findings of the present study suggest that AKT is pivotal in gastric carcinogenesis and progression.

Intestinal Stem Cell Markers in the Intestinal Metaplasia of Stomach and Barrett's Esophagus

Gastric intestinal metaplasia (IM) is a highly prevalent preneoplastic lesion; however, the molecular mechanisms regulating its development remain unclear. We have previously shown that a population of cells expressing the intestinal stem cell (ISC) marker LGR5 increases remarkably in IM. In this study, we further investigated the molecular characteristics of these LGR5⁺ cells in IM by examining the expression profile of several ISC markers. Notably, we found that ISC markers—including OLFM4 and EPHB2—are positively associated with the CDX2 expression in non-tumorous gastric tissues. This finding was confirmed in stomach lesions with or without metaplasia, which demonstrated that OLFM4 and EPHB2 expression gradually increased with metaplastic progression. Moreover, RNA in situ hybridization revealed that LGR5⁺ cells coexpress several ISC markers and remained confined to the base of metaplastic glands, reminiscent to that of normal intestinal crypts, whereas those in normal antral glands expressed none of these markers. Furthermore, a large number of ISC marker-expressing cells were diffusely distributed in gastric adenomas, suggesting that these markers may facilitate gastric tumorigenesis. In addition, Barrett’s esophagus (BE)—which is histologically similar to intestinal metaplasia—exhibited a similar distribution of ISC markers, indicating the presence of a stem cell population with intestinal differentiation potential. In conclusion, we identified that LGR5⁺ cells in gastric IM and BE coexpress ISC markers, and exhibit the same expression profile as those found in normal intestinal crypts. Taken together, these results implicate an intestinal-like stem cell population in the pathogenesis of IM, and provide an important basis for understanding the development and maintenance of this disease.

Intestinal metaplasia of the sinonasal mucosa adjacent to intestinal-type adenocarcinoma. A morphologic, immunohistochemical, and molecular study

It has been hypothesized that the development of sinonasal intestinal-type adenocarcinoma (ITAC) occurs through intestinal metaplasia (IM) of the respiratory and/or glandular epithelium. The aim of this study was to characterize the histological, immunohistochemical, and molecular features of sinonasal IM. Histologic slides from 29 consecutive surgical specimens of ITAC were retrieved. Sections were stained for CDX2, cytokeratin 20 (CK20), MUC2, and p53. The status of TP53 gene exons 4-9 was assessed separately in areas of IM and in ITAC. Foci of IM were detected in eight cases (27.5%). They were all positive for CK20 and CDX2, while MUC2 was detected in six cases (75%). In six cases (75%), the metaplastic foci showed signs of dysplasia, including nuclear enlargement with increased nucleus to cytoplasm ratio, nuclear hyperchromasia, loss of nuclear polarity, and presence of prominent nucleoli. P53 nuclear immunoreactivity was observed in four cases. TP53 gene sequencing was successfully performed in six cases and revealed the same mutation in both IM and ITAC in two cases (c.832C > T and c.215G > C), while another ITAC showed a mutation that was not present in the adjacent IM (c.536A > G). In conclusion, our study suggests a possible clonal relationship between areas of sinonasal IM and ITAC, indicating that IM may represent a precursor lesion of ITAC. Improving the knowledge on the morphological and molecular features of IM is a key step to identify reliable biomarkers to determine the risk of sinonasal ITAC development.

Present and future status of flexible spectral imaging color enhancement and blue laser imaging technology

The usefulness of flexible spectral imaging color enhancement (FICE) has been reported for evaluating the esophagus, stomach, and small and large intestine. Higher contrast is shown between cancer and the surrounding mucosa in the esophagus and stomach and may facilitate the detection of gastric cancers missed by white light imaging alone. The surface patterns of gastric mucosa are clearly visualized in non-malignant areas but are irregular and blurred in malignant areas, leading to clear demarcation. Capsule endoscopy with FICE detects angiodysplasia and erosions of the small intestine. The surface and vascular pattern with FICE is useful for the differential diagnosis of colorectal polyps. However, FICE remains somewhat poor at visualizing mucosal microvasculature on a tumor surface. Narrow-band imaging (NBI) is dark in observing whole gastric mucosa and poor at visualizing mucosal microstructure. Blue laser imaging (BLI) has the potential to resolve these limitations. Narrow-band laser light combined with white light shows irregular microvessels on both differentiated and undifferentiated gastric cancer similar to those using NBI. In addition, irregular surface patterns including minute white zones are clearly seen on the uneven surface of differentiated lesions, resulting in exclusion of undifferentiated lesions. Using both distant and close-up views, a high contrast between green intestinal metaplasia and brown gastric cancer may lead to early detection of gastric cancers and determination of a demarcation line. BLI produces high-contrast images in esophageal cancer with clear vision of intrapapillary capillary loops and also predicts the histopathological diagnosis and depth of invasion in colorectal neoplasms.

Inhibition of Hedgehog signaling in the gastrointestinal tract: targeting the cancer microenvironment

This review summarizes emerging information regarding the Hedgehog (Hh) signaling pathway during neoplastic transformation in the gastrointestinal tract. Although there is a role for the well-established canonical pathway in which Hedgehog ligands interact with their receptor Patched, there is sufficient evidence that downstream components of the Hh pathway, e.g., Gli1, are hijacked by non-Hh signaling pathways to promote the conversion of the epithelium to dysplasia and carcinoma. We review the canonical pathway and involvement of primary cilia, and then focus on current evidence for Hh signaling in luminal bowel cancers as well as accessory organs, i.e., liver, pancreas and biliary ducts. We conclude that targeting the Hh pathway with small molecules, nutriceuticals and other mechanisms will likely require a combination of inhibitors that target Gli transcription factors in addition to canonical modulators such as Smoothened.