Two Distinct Etiologies of Gastric Cancer: Infection and Autoimmunity

Gastric cancer is a leading cause of mortality worldwide. The risk of developing gastric adenocarcinoma, which comprises >90% of gastric cancers, is multifactorial, but most associated with Helicobacter pylori infection. Autoimmune gastritis is a chronic autoinflammatory syndrome where self-reactive immune cells are activated by gastric epithelial cell autoantigens. This cause of gastritis is more so associated with the development of neuroendocrine tumors. However, in both autoimmune and infection-induced gastritis, high risk metaplastic lesions develop within the gastric mucosa. This warrants concern for carcinogenesis in both inflammatory settings. There are many similarities and differences in disease progression between these two etiologies of chronic gastritis. Both diseases have an increased risk of gastric adenocarcinoma development, but each have their own unique comorbidities. Autoimmune gastritis is a primary cause of pernicious anemia, whereas chronic infection typically causes gastrointestinal ulceration. Both immune responses are driven by T cells, primarily CD4+ T cells of the IFN-γ producing, Th1 phenotype. Neutrophilic infiltrates help clear H. pylori infection, but neutrophils are not necessarily recruited in the autoimmune setting. There have also been hypotheses that infection with H. pylori initiates autoimmune gastritis, but the literature is far from definitive with evidence of infection-independent autoimmune gastric disease. Gastric cancer incidence is increasing among young women in the United States, a population at higher risk of developing autoimmune disease, and H. pylori infection rates are falling. Therefore, a better understanding of these two chronic inflammatory diseases is needed to identify their roles in initiating gastric cancer.

Chronic Autoimmune Gastritis: Modern Diagnostic Principles

This article summarizes and systematizes the available data from the literature on chronic autoimmune gastritis (CAG) in order to increase the awareness of specialists about the modern possibilities for diagnosing the disease, including its early stages. The clinical manifestation of the disease includes possible variants such as gastrointestinal, hematological (first of all, the formation of iron deficiency and B12-deficiency anemia), and neurological variants. Patients with chronic autoimmune gastritis are characterized by comorbidity with other autoimmune diseases. In this paper, data on the most informative serological markers for the diagnosis of CAG, as well as laboratory tests to detect micronutrient deficiencies, information on the characteristic changes in the gastric mucosa, and the prognosis of the disease, are presented. The diagnosis of CAG should be based on a multidisciplinary approach that combines a thorough analysis of a patient’s complaints with a mandatory assessment of nutritional status, as well as the results of serological, endoscopic, and histological research methods.

Histologic features in an autoimmune gastritis patient with hypergastrinemia: Call for a grading system for G cell hyperplasia

Introduction/Objective Autoimmune gastritis (AG) is characterized by oxyntic glands destruction, metaplasia, enterochromaffin-like endocrine cell abnormality and G-cell hyperplasia with hypergastrinemia. The gastrin level can be extraordinarily high in certain cases to justify suspicion of Zollinger-Ellison syndrome. We herein report one such case and discuss clinical implication of a grading system for G-cell hyperplasia to correlate histology with gastrin levels. Methods/Case Report The patient was a symptomatic 65 year-old female with hypergastrinemia (2,068 pg/mL), negative abdomen/pelvis CT scan, positive anti-intrinsic factor and anti-parietal cell antibodies. Under esophagogastroduodenoscopy, biopsies were obtained from gastric cardia, fundus, corpus, incisura angularis, and antrum. Morphology and immunostains confirmed autoimmune gastritis. Diffuse linear pattern G-cell hyperplasia was evident in antrum and incisura angularis, counting up to 200 G-cells per linear millimeter. One study defined G-cell hyperplasia as >140 gastrin-positive cells per linear millimeter while another proposed a 2-tier stratification, i.e., simple hyperplasia (4-5 cells for each gland) and linear hyperplasia (continuous chain-like distribution of G-cells). Such scoring, however, was largely qualitative and fell short in delineating the extent of G-cell hyperplasia and correlation with gastrinemia. Results (if a Case Study enter NA) NA Conclusion Lack of G-cell grading system hindered our unequivocal determination of the G-cell hyperplasia as underlying or contributing cause of hypergastrenemia. The unique features of our case highlighted the necessity for installing a practical grading system that incorporates G-cell density, pattern (linear vs. nodular), extent of involved areas, other features of AG to correspond to gastrin level. With accumulation of clinical information, one such grading system is feasible and will improve our knowledge and patient care.