On the origin of gastric tumours: analysis of a case with intramucosal gastric carcinoma and oxyntic gland adenoma

Evaluating the detection rate and pathological features of polyps in patients with upper gastrointestinal endoscopy

BACKGROUND

The incidence of gastric polyps (GPs) has ranged from 0.30% to 6.8% in various studies. Most GPs include hyperplastic polyps (HPs), fundic gland polyps (FGPs), and adenomatous polyps (APs). Although APs have a high malignant potential, HPs have a low risk of potential harm, whereas sporadic FGPs have no malignant potential. It is not enough to determine the type and displacement of a polyp by biopsy alone; therefore, some polyps may require an extensive biopsy or complete resection.

AIM

To evaluate the detection rate and pathological features of polyps in patients undergoing upper gastrointestinal endoscopy.

METHODS

This retrospective study included patients with GPs or polyphenic lesions with polyps or malignant histology found in polyps or by gastroscopy at the Department of Gastroenterology at the Shaanxi Provincial Hospital of Traditional Chinese Medicine from 2019 to 2023.

RESULTS

In a series of 10000 patients who underwent upper gastrointestinal endoscopy, 384 (3.84%) had GPs. There were 98 males (25.5%) and 286 females (74.5%). The mean age of patients was 62.8 ± 10.4 (36-75) years. The frequencies of HPs, APs, and FGPs were 88.5%, 5.2%, and 2.1%, respectively. The polyp size of 274 patients (71.3%) was ≤ 1 cm. Polyps were found in 262 cases (68.2%). The most common sites for polyps were the lumen and body of the intestine. Endoscopic polypectomy was performed in 128 patients. Bleeding events were observed and endoscopic treatment was required after endoscopic polypectomy.

CONCLUSION

The incidence of GPs was low. HPs were the most common types of GPs. Of note, as GPs have the potential to develop into adenocarcinoma or precancerous lesions, we suggest that appropriate GP resection technology (e.g., biopsy forceps or mesenchymal resection) be applied.

Helicobacter pylori, microbiota and gastric cancer - principles of microorganism-driven carcinogenesis

The demonstration that Helicobacter pylori is a pathogenic bacterium with marked carcinogenic potential has paved the way for new preventive approaches for gastric cancer. Although decades of research have uncovered complex interactions of H. pylori with epithelial cells, current insights have refined our view on H. pylori-associated carcinogenesis. Specifically, the cell-type-specific effects on gastric stem and progenitor cells deep in gastric glands provide a new view on the ability of the bacteria to colonize long-term, manipulate host responses and promote gastric pathology. Furthermore, new, large-scale epidemiological data have shed light on factors that determine why only a subset of carriers progress to gastric cancer. Currently, technological advances have brought yet another revelation: H. pylori is far from the only microorganism able to colonize the stomach. Instead, the stomach is colonized by a diverse gastric microbiota, and there is emerging evidence for the occurrence and pathological effect of dysbiosis resulting from an aberrant interplay between H. pylori and the gastric mucosa. With the weight of this evidence mounting, here we consider how the lessons learned from H. pylori research inform and synergize with this emerging field to bring a more comprehensive understanding of the role of microbes in gastric carcinogenesis.

Origin of Peritoneal Cancer With Features of High-grade Serous Carcinoma: A Detailed Molecular Analysis

Primary peritoneal cancer has characteristics similar to high-grade serous carcinomas of ovarian and fallopian tube origin. However, the relationship between endometriosis and primary peritoneal cancer is not well understood. This study focuses on a case of peritoneal cancer in a patient who had undergone hysterectomy and bilateral salpingo-oophorectomy 5 yr before. In addition to morphology, there was a positive for TP53 in immunohistochemistry and homologous recombination deficiency test, which were similar to high-grade serous carcinomas. However, WT1 was negative in the tumor, and extensive endometriosis coexisted. To reveal the clonal relationship between tumor and endometriosis, we dissected 3 sites each from the tumor and endometriosis and performed whole-exome sequencing analysis. As a result, we found that the tumors were of identical origin. Contrarily, no shared mutations were found in the 3 endometriosis sites. Furthermore, several shared mutations were found between the tumor and 1 endometriosis tissue, showing that the tumor and 1 ectopic endometrial gland originated from the same clone. This study indicates that several peritoneal cancers may be derived from endometriosis. We should consider the possibility of more diverse origins of peritoneal cancer than we speculated before.

Contract to kill: GNAS mutation

The mutation in Gsα-coding GNAS exons, popular as gsp oncogene, is the most frequent mutation across all heterotrimeric G proteins involved in oncogenesis. GNAS R201, the most frequently mutated, followed by Q227, are found predominantly across various neoplasms and cancers such as IPMN, pituitary, thyroid, appendiceal, colorectal, etc. This review emphasizes the pivotal significance of the gsp oncogene and its ramifications underpinning the sustained addiction to GNAS mutation. Recent studies delineating the mechanistic intricacies that provide solid evidence of the profound impact of oncogenic GNAS on tumor formation, progression, and maintenance are highlighted. We have leveraged the discoveries of Gsα as an ideal neoantigen candidate for vaccine therapy, allele-specific inhibitors, and cyclic peptide-based small molecular inhibitors for G proteins and explored the therapeutic potential to target oncogenic GNAS directly. Alternative therapeutic modalities and patient-centric studies to mitigate the impact of GNAS mutations are also discussed. The exposition of novel studies and strategies designed to address the potential challenges inherent in these approaches of targeting the activating mutations of GNAS, along with probable avenues for further investigation, are highlighted. This review aims to reverberate the current understanding of the oncogenic potential of GNAS, the genomic and biological landscape of GNAS-driven neoplasms and cancers, and potential therapeutic strategies against them.

Antarmycins: Discovery, Biosynthesis, Anti-pathogenic Bacterial Activity, and Mechanism of Action from Deep-Sea-Derived Pseudonocardia antarctica

The rapid emergence of antimicrobial-resistant pathogenic microbes has accelerated the search for novel therapeutic agents. Here we report the discovery of antarmycin A (1), an antibiotic containing a symmetric 16-membered macrodiolide core with two pendant vancosamine moieties, one of which is glucosylated, from deep-sea-derived Pseudonocardia antarctica SCSIO 07407. The biosynthetic gene cluster of 1 was identified on a giant plasmid featuring transferable elements. In-depth biosynthetic investigation enabled us to (i) identify a set of seven genes associated with the product of the vancosamine moiety; (ii) discover two glycosyltransferases dedicated to the transfer of pendant sugars; and (iii) isolate rhamnose-modified antarmycin B (2) and a deglucosylated derivative antarmycin C (3) from genetically engineered mutant strains. Antibacterial assays revealed that 1 displays superior antibacterial properties with potent in vitro activities against the critical priority pathogens, multidrug-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus, fast bacterial killing, insusceptibility to antimicrobial resistance, and high in vivo efficiency in infection models. Mechanistic investigations revealed that 1 disrupts the bacterial cell membrane through a mechanism involving interactions between the vancosamine moieties and membrane-embedded phosphatidylglycerol/phosphatidylethanolamine. The results provide insights into the biological generation of vancosamine in natural products and demonstrate the potential of 1 as an effective lead to address the growing antimicrobial resistance threats.

H. Pylori-Facilitated TERT/Wnt/β-Catenin Triggers Spasmolytic Polypeptide-Expressing Metaplasia and Oxyntic Atrophy

Persistent H. pylori infection triggers the repair program of the mucosa, such as spasmolytic polypeptide-expressing metaplasia (SPEM). However, the mechanism underlying the initiation of SPEM in gastric tissues by H. pylori remains unclear. Here, an increase in telomerase reverse transcriptase (TERT) protein expression is observed in chief cells upon infection with cagA-positive H. pylori. Tert knockout significantly ameliorated H. pylori-induced SPEM and single-cell RNA sequencing demonstrated that the Wnt/β-Catenin pathway is suppressed in gastric cells with Tert knockout. Mechanism study revealed that CagA elevated TERT abundance by disrupting the interaction between TERT and its novel E3 ligase, SYVN1. Interestingly, Nitazoxanide effectively relieved SPEM via inhibition of the Wnt/β-Catenin signaling in vivo. This results clarified the mechanism underlying which CagA activated the TERT/Wnt/β-Catenin pathway, thus promoting the dedifferentiation of chief cells and the occurrence of SPEM in gastric mucosa. This highlights a molecular basis for targeting CagA-activated Wnt signaling in chief cells for the treatment of gastric precancerous lesions.

Refining the diagnostic utility of OLFM4 in gastric cancer precursors: a call for rigorous methodologies

This commentary offers a thoughtful discussion of the study by Wei et al. published in the journal on the role of Olfactomedin 4 (OLFM4) in incomplete intestinal metaplasia, a gastric precancerous condition. The original paper introduces OLFM4 as a novel biomarker with potential enhanced diagnostic efficacy compared to established markers. However, several methodological and interpretive considerations are noted. The histopathological findings could be refined by using higher magnification to better elucidate the cellular localization of OLFM4. Including high-resolution images for key stainings would enhance the study's robustness in expression profiling. The statistical approach could be strengthened by employing more rigorous, quantitative methodologies. Additionally, integrating immunofluorescence double-staining may improve the reliability of the results. Discrepancies in immunohistochemical signals across datasets suggest a need for further investigation into tissue section representativeness. Clarifying the term "precancerous lesions of gastric carcinoma cells" to align with widely accepted definitions would enhance clarity. The choice of the GES-1 cell model treated with MNNG could be reconsidered in favor of more established models such as organoids, air-liquid interface models, and gastric cancer-specific cell lines. The in vivo MNNG-alcohol combination model might require additional empirical support, given the limited and conflicting literature on this approach, to ensure an accurate portrayal of IM pathogenesis. The commentary concludes with a call for stringent and standardized methodologies in biomarker research to ensure the clinical applicability and reliability of biomarker studies, particularly in the context of gastric cancer detection and intervention.

[Oxyntic gland neoplasia - case report and diagnostic dilemma]

Az oxynticus mirigy neoplasia terminológia a gyomor olyan atípusos fő- és fedősejtek által alkotott mirigyei esetében használatos, amikor nem látszik invázió, tehát a fundus mirigy adenocarcinoma diagnózisa nem állítható fel, ugyanakkor a laesio nem került kompletten eltávolításra, tehát teljes vastagsága nem vizsgálható. Az oxynticus mirigy neoplasiák etiológiája jelenleg tisztázatlan, egyes források protonpumpagátlókkal, valamint antihisztamin-használattal hozták őket összefüggésbe. Endoszkópos vizsgálat során a morfológiájuk nem specifikus, lapos és polypoid laesiók egyaránt lehetnek, és döntően a gyomor felső egyharmadára lokalizáltak. Amennyiben komplett endoszkópos nyálkahártya-reszekció kivitelezhető, további kezelés nem szükséges, tehát összességében jó prognózisú elváltozásoknak tarthatók. Közleményünkben egy 84 éves nő esetét mutatjuk be, akinél haspuffadás miatt indult kivizsgálás, és gasztroszkópia történt. A corpus területén 1 cm-es, lapos polypus volt látható, melyből többszörös biopszia történt, a képlet közel teljes eltávolításával. A szövettani vizsgálat során a nyálkahártya mélyén jól körülírt és jól differenciált, expanzív szélű elváltozás volt megfigyelhető, melyet atípusos fősejtek, elvétve pedig fedősejtek alkottak. Ezek a sejtek oxynticusmirigy-szerű struktúrákat képeztek. A pepszinogénreakció a fősejtekben szemcsés jellegű, citoplazmatikus pozitivitást mutatott. H+/K+ ATPáz reakcióval a fedősejtekben szintén szemcsés jellegű, citoplazmatikus pozitivitás látszott. MUC6-tal a laesionalis sejtekben diffúz, citoplazmatikus pozitivitás volt megfigyelhető. Invázió jeleit nem láttuk. A morfológiai, valamint az immunfenotípus alapján is az elváltozást oxynticus mirigy neoplasiának véleményeztük, ’low-grade’ dysplasiával. Az oxynticus mirigy neoplasiák mind klinikai, mint patológiai szempontból fokozott figyelmet igényelnek, ugyanis ritka entitásokról van szó, melyeknek egyelőre sem az etiológiájuk, sem a prognózisuk nem tisztázott teljes mértékben. Differenciáldiagnosztikai szempontból fundus mirigy polypus, pylorus mirigy adenoma, valamint neuroendokrin tumor jön szóba. A definitív diagnózis felállítását pepszinogén, H+/K+ ATPáz, valamint MUC6 immunhisztokémiai reakciók segíthetik. Orv Hetil. 2024; 165(27): 1053–1057.

Gastric epithelial neoplasm of fundic-gland mucosa lineage: representative of the low atypia differentiated gastric tumor and Ki67 may help in their identification

Background

Gastric epithelial neoplasm of the fundic-gland mucosa lineages (GEN-FGMLs) are rare forms of gastric tumors that encompass oxyntic gland adenoma (OGA), gastric adenocarcinoma of the fundic-gland type (GA-FG), and gastric adenocarcinoma of the fundic-gland mucosa type (GA-FGM). There is no consensus on the cause, classification, and clinicopathological features of GEN-FGMLs, and misdiagnosis is common because of similarities in symptoms.

Methods

37 cases diagnosed with GEN-FGMLs were included in this study. H&E-stained slides were reviewed and clinicopathological parameters were recorded. Immunohistochemical staining was conducted for MUC2, MUC5AC, MUC6, CD10, CD56, synaptophysin, chromograninA, p53, Ki67, pepsinogen-I, H+/K+-ATPase and Desmin.

Results

The patients' ages ranged from 42 to 79 years, with a median age of 60. 17 were male and 20 were female. Morphologically, 19 OGAs, 16 GA-FGs, and two GA-FGMs were identified. Histopathological similarities exist between OGA, GA-FG, and GA-FGM. The tumors demonstrated well-formed glands, expanding with dense growth patterns comprising pale, blue-grey columnar cells with mild nuclear atypia. These cells resembled fundic gland cells. None of the OGA invaded the submucosal layer. The normal gastric pit epithelium covered the entire surface of the OGA and GA-FG, but the dysplasia pit epithelium covered the GA-FGM. Non-atrophic gastritis was observed in more than half of the background mucosa. All cases were diffusely positive for MUC6 and pepsinogen-I on immunohistochemistry. H+/K+-ATPase staining was negative or showed a scattered pattern in most cases. MUC5AC was expressed on the surface of GA-FGMs. p53 was focally expressed and the Ki67 index was low (1%-20%). Compared with OGA, GA-FG and GA-FGM were more prominent in the macroscopic view (p < 0.05) and had larger sizes (p < 0.0001). Additionally, GA-FG and GA-FGM exhibited higher Ki67 indices than OGA (p < 0.0001). Specimens with Ki-67 proliferation indices >2.5% and size >4.5 mm are more likely to be diagnosed with GA-FG and GA-FGM than OGA.

Conclusion

GEN-FGMLs are group of well-differentiated gastric tumors with favourable biological behaviours, low cellular atypia, and low proliferation. Immunohistochemistry is critical for confirming diagnosis. Compared with OGA, GA-FG and GA-FGM have larger sizes and higher Ki67 proliferation indices, indicating that they play a critical role in the identification of GEN-FGML. Pathologists and endoscopists should be cautious to prevent misdiagnosis and overtreatment, especially in biopsy specimens.

Spasmolytic polypeptide-expressing metaplasia (SPEM) cell lineages can be an origin of gastric cancer

Intestinal-type gastric cancer arises in a field of precancerous metaplastic lineages. Two types of metaplastic glands are found in the stomachs of humans with the characteristics of pyloric metaplasia or intestinal metaplasia. While spasmolytic polypeptide-expressing metaplasia (SPEM) cell lineages have been identified in both pyloric metaplasia and incomplete intestinal metaplasia, it has been unclear whether SPEM lineages or intestinal lineages can give rise to dysplasia and cancer. A recent article published in The Journal of Pathology describes a patient with evidence of an activating Kras(G12D) mutation in SPEM that is propagated into adenomatous and cancerous lesions which manifest further oncogenic mutations. This case therefore supports the concept that SPEM lineages can serve as a direct precursor for dysplasia and intestinal-type gastric cancer. © 2023 The Pathological Society of Great Britain and Ireland.

Gastric Stem Cell Biology and Helicobacter pylori Infection

Helicobacter pylori colonizes the human gastric mucosa and persists lifelong. An interactive network between the bacteria and host cells shapes a unique microbial niche within gastric glands that alters epithelial behavior, leading to pathologies such as chronic gastritis and eventually gastric cancer. Gland colonization by the bacterium initiates aberrant trajectories by inducing long-term inflammatory and regenerative gland responses, which involve various specialized epithelial and stromal cells. Recent studies using cell lineage tracing, organoids and scRNA-seq techniques have significantly advanced our knowledge of the molecular "identity" of epithelial and stromal cell subtypes during normal homeostasis and upon infection, and revealed the principles that underly stem cell (niche) behavior under homeostatic conditions as well as upon H. pylori infection. The activation of long-lived stem cells deep in the gastric glands has emerged as a key prerequisite of H. pylori-associated gastric site-specific pathologies such as hyperplasia in the antrum, and atrophy or metaplasia in the corpus, that are considered premalignant lesions. In addition to altering the behaviour of bona fide stem cells, injury-driven de-differentiation and trans-differentation programs, such as "paligenosis", subsequently allow highly specialized secretory cells to re-acquire stem cell functions, driving gland regeneration. This plastic regenerative capacity of gastric glands is required to maintain homeostasis and repair mucosal injuries. However, these processes are co-opted in the context of stepwise malignant transformation in chronic H. pylori infection, causing the emergence, selection and expansion of cancer-promoting stem cells.