Role of Autoimmune Gastritis in Gastric Cancer

Biofabrication of bimetallic selenium@zinc nanoparticles using Champia parvula aqueous extract: Investigation of anticancer activity and its apoptosis induction

Selenium@zinc nanoparticles, or Se@Zn NPs, are extensively employed in various environmental, industrial and biological domains. However, the biological potential of Se@Zn NPs has not been thoroughly investigated. This study focused on fabricating Se@Zn NPs from algae using an aqueous extract of Champia parvula seaweed. Analytical techniques were used to describe the successfully synthesized Se@Zn NPs. In addition, a biological function analysis of the Se@Zn NPs was conducted. The Ultraviolet-visible spectroscopy (UV-vis) spectrum showed a specific absorbance peak for the Se@Zn NPs at 350-400 nm. The biomolecules involved in forming Se@Zn NPs were identified by their potential functional groups, as revealed by Fourier transform infrared spectroscopy (FTIR). By scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Se@Zn NPs were shown to be spherical and to have a diameter range of 100-200 nm. NPs with a crystallite diameter of 54.8 nm and chemical compositions of zinc and selenium (1:1.5 ratio) were revealed by X-ray diffraction analysis (XRD) and energy dispersive x-ray spectroscopy (EDS). IC50 values were determined for the anticancer activity against A549, MCF-7 and HeLa cells. Cell morphological changes in fluorescence microscopy and apoptosis mechanisms by flow cytometry analysis were investigated, which show that Se@Zn NPs induced apoptosis in various cancer cells. DNA fragmentation and ROS levels were studied by fluorescence microscopy. In conclusion, conditions required for therapeutic and preventative applications may be met by the green synthesis of Se@Zn NPs.

Autoimmune Gastritis and Hypochlorhydria: Known Concepts from a New Perspective

Autoimmune atrophic gastritis is an immune-mediated disease resulting in autoimmune destruction of the specialized acid-producing gastric parietal cells. As a consequence, in autoimmune atrophic gastritis, gastric acid secretion is irreversibly impaired, and the resulting hypochlorhydria leads to the main clinical manifestations and is linked, directly or indirectly, to the long-term neoplastic complications of this disease. In the last few years, autoimmune atrophic gastritis has gained growing interest leading to the acquisition of new knowledge on different aspects of this disorder. Although reliable serological biomarkers are available and gastrointestinal endoscopy techniques have substantially evolved, the diagnosis of autoimmune atrophic gastritis is still affected by a considerable delay and relies on histopathological assessment of gastric biopsies. One of the reasons for the diagnostic delay is that the clinical presentations of autoimmune atrophic gastritis giving rise to clinical suspicion are very different, ranging from hematological to neurological-psychiatric up to gastrointestinal and less commonly to gynecological-obstetric symptoms or signs. Therefore, patients with autoimmune atrophic gastritis often seek advice from physicians of other medical specialties than gastroenterologists, thus underlining the need for increased awareness of this disease in a broad medical and scientific community.

The central role of gastrin in gastric cancer

The prevalence of gastric cancer has markedly declined, but due to the high mortality rates associated with gastric cancer, it is still a serious disease. The preferred classification of gastric cancer is according to Lauren into either the intestinal type, which has a glandular growth pattern, or the diffuse type, which does not have glandular structures. Both types have been classified as adenocarcinomas, with the latter type based on periodic acid-Schiff (PAS) positivity presumed to reflect mucin. However, the presence of mucin in the diffuse type, in contrast to neuroendocrine/enterochromaffin-like (ECL) cell markers, has not been confirmed by immunohistochemistry and in situ hybridization. The ECL cells are probably prone to becoming cancerous because they do not express E-cadherin. Gastric cancer is unique in that a bacterium, Helicobacter pylori, is thought to be its main cause. H. pylori predisposes infected individuals to cancer only after having caused oxyntic atrophy leading to gastric hypoacidity and hypergastrinemia. No single H. pylori factor has been convincingly proved to be carcinogenic. It is probable that gastrin is the pathogenetic factor for gastric cancer due to H. pylori, autoimmune gastritis, and long-term prolonged inhibition of gastric acid secretion. Hypergastrinemia induces ECL cell hyperplasia, which develops into neuroendocrine tumors (NETs) and then into neuroendocrine carcinomas in rodents, a sequence that has also been described in humans. During carcinogenesis, the tumor cells lose specific traits, requiring that sensitive methods be used to recognize their origin. Gastric cancer occurrence may hopefully be prevented by H. pylori eradication at a young age, and by the reduced use of inhibitors of acid secretion and use of a gastrin antagonist in those with previous long-term H. pylori infection and those with autoimmune gastritis.

Impact of Autoimmune Gastritis on Occurrence of Metachronous Gastric Neoplasms after Endoscopic Resection for Gastric Neoplasms

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. Autoimmune gastritis (AIG) is characterized by antibody production against the gastric parietal cells, reducing the number of functional parietal cells. It is also associated with an increased susceptibility to gastric neuroendocrine tumors and gastric cancer. Endoscopic resection (ER) is an effective treatment for early gastric cancer; however, metachronous gastric neoplasms (MGN) can develop. This study aimed to evaluate the clinical effect of AIG on the occurrence of MGN after ER for gastric neoplasms. We retrospectively analyzed patients who underwent ER for gastric neoplasms. Patients with multiple lesions, recurrent lesions, or a history of partial gastrectomy were excluded. The presence of AIG was determined using anti-parietal cell antibody (APCA) testing. Follow-up endoscopy and metachronous tumor occurrence rates were compared between the AIG and non-AIG groups. Of the 569 patients, 282 underwent APCA testing and 20 (7.1%) were diagnosed with AIG. The incidence of MGN was significantly higher in the AIG group than in the non-AIG group (45.0% vs. 18.3%); however, the MGN occurrence pattern was similar between the two groups. Multivariate analysis revealed that AIG (HR 3.32, 95% CI 1.55-7.10, p = 0.002) and a higher body mass index (HR 1.16, 95% CI 1.06-1.27, p = 0.002) were independent factors significantly associated with the occurrence of MGN. Patients with AIG have a higher risk of metachronous lesion occurrence after ER for gastric neoplasms. Positive results of APCA testing have independent clinical implications for predicting MGN. Proper monitoring and management are essential for early detection and treatment of recurrent lesions in patients with AIG.

[Metachronous tumors of the stomach in a patient with autoimmune gastritis]

Stomach cancer continues to be a global health problem, ranking 5th among cancers and 4th among the causes of death from cancer in the world. Autoimmune atrophic gastritis is a chronic autoimmune disease characterized by the production of antibodies to parietal cells and intrinsic factor, followed by atrophy of the mucous membrane of the body and fundus of the stomach. Chronic autoimmune inflammation can lead to damage to the genetic apparatus of the cell and trigger a multi-stage process of carcinogenesis. Our article presents an unusual case of three different gastric tumors, including adenocarcinoma with microsatellite instability, in a patient with autoimmune gastritis.

Tumor Classification Should Be Based on Biology and Not Consensus: Re-Defining Tumors Based on Biology May Accelerate Progress, An Experience of Gastric Cancer

Simple Summary

Rational treatment of diseases including cancers depends on knowledge of their cause as well as their development. The present review is based upon more than 40 years’ work in clinical gastroenterology, gastric physiology, and pathology. The central role of hormones as well as local endocrine cells in cancer development has become apparent. Moreover, the classification of tumors should focus not only on the organ of origin but also on the cell of origin. All cells with the ability to divide may give rise to tumors. Based upon knowledge of the growth regulation of the cell of origin, prophylaxis and treatment may be tailored. Presently, there is hope for individual treatment of cancer patients based upon genetic analyses of tumors. However, with correct identification of the cell of origin, this may not be necessary.

Abstract

Malignant tumors are a consequence of genetic changes mainly occurring during cell division, sometimes with a congenital component. Therefore, accelerated cell divisions will necessarily predispose individuals, whether due to conditions of chronic cell destruction or hormonal overstimulation. It has been postulated that two genetic hits are necessary for the development of malignancy (Knudson). The correct view is probably that the number of genetic changes needed depends on the role the mutated genes have in proliferation and growth control. Hormones should accordingly be regarded as complete carcinogens. In this review based upon experience of gastric cancer where gastrin is central in the pathogenesis, it is argued that oxyntic atrophy—and not metaplasia as postulated by Correa—is the central precancer change in gastric mucosa. Moreover, the target cell of gastrin, the enterochromaffin-like (ECL) cell, is central in gastric carcinogenesis and most probably the cell of origin of gastric carcinomas of the diffuse type according to Lauren (a classification probable in accordance with biology). The distinction between adenocarcinomas and neuroendocrine carcinomas based upon a certain percentage of cancer cells with neuroendocrine differentiation is questioned. To make progress in the treatment of cancer, a correct classification system and knowledge of the pathogenesis are necessary.

Distinct Features of Autoimmune Gastritis in Patients with Open-Type Chronic Gastritis in Japan

In Asia, the incidences of Helicobacter pylori infection and gastric cancer are high, but their association with autoimmune gastritis (AIG) is unclear. This was a retrospective cohort study of patients endoscopically diagnosed with chronic gastritis between 2005 and 2017. AIG was diagnosed according to anti-parietal cell antibody positivity. Laboratory, histological findings, and gastric cancer incidence were compared between AIG and non-AIG patients. The AIG group had more females and a higher rate of thyroid disease. Serum levels of gastrin were significantly higher in AIG patients (mean 1412 and 353 pg/mL, p < 0.001). The endoscopic findings included a significantly higher percentage of corpus-dominant atrophy in AIG (31.67%) than in non-AIG (7.04%) patients (p < 0.001). Clusters of ECL cells were observed in 28% of AIG patients and 7% of non-AIG patients (p = 0.032). The cumulative incidence of gastric cancer at 5 and 10 years was 0% and 0.03% in the AIG group and 0.03% and 0.05% in the non-AIG group, and no significant difference in gastric cancer incidence was observed. Despite significant differences in gastrin levels between AIG and non-AIG patients, there was no evidence of an impact of AIG on the incidence of gastric cancer.

Clinical consequences of controversies in gastric physiology

Studies on the regulation of gastric acid secretion started more than 100 years ago at an early phase of experimental physiology. In nearly the whole last century there were disputes about the interpretation of the findings: the interaction between the three principle gastric acid secretagogues acetylcholine, gastrin and histamine, the cell producing the relevant histamine which turned out to be the ECL cell, the ability of the ECL cell to divide and thus develop into tumours, the classification of gastric carcinomas and the mechanism for Helicobacter pylori carcinogenesis. The elucidation of the central role of the ECL cell and thus its main regulator, gastrin, solve all these controversies, and gives a solid base for handling upper gastrointestinal diseases.

Male Predominance of Gastric Cancer among Patients with Hypothyroidism from a Defined Geographic Area

In the past, hypothyroidism has been associated with an increased susceptibility to gastric cancer (GC). Although several epidemiological studies have corroborated this association, a precise mechanistic explanation remains elusive. In this study, this hypothesis was tested by using a large database of subjects who underwent upper endoscopy for various reasons. This was a retrospective, case-control, single-center study. Subjects with GC (cases) were compared with subjects without (controls), according to hypothyroidism status. Overall, the prevalence of GC was 0.73% in the total cohort and was significantly higher in males compared to females (1.4% versus 0.4%, p < 0.0001). Multivariate logistic regression analysis confirmed an increased risk in males with hypothyroidism (OR 5.10; p < 0.0001) after adjusting for potential confounders, especially H. pylori infection. Interestingly, only hypothyroidism and not treatment with levothyroxine was a significant predictor of GC, ruling out a possible direct carcinogenic effect of the replacement therapy. The present study suggests a male-restricted association of gastric carcinogenesis with a hypothyroid state. If the results of this study are confirmed by longitudinal studies, an attractive perspective could open up for the better management of males with concomitant hypothyroidism and a higher risk of GC.