Antibodies Against Epstein-Barr Virus as Disease Markers of Gastric Cancer: A Systematic Review.

Introduction: Gastric cancer is the fourth deadliest cancer worldwide. Due to the lack of specific early symptoms and noninvasive methods for early detection, the prognosis of gastric cancer patients is poor. Gastric cancer has a well-recognized infectious etiology, with Helicobacter pylori and Epstein-Barr Virus being the main associated infectious agents. Although other Epstein-Barr Virus-associated malignancies often manifest with abnormal levels of anti-Epstein-Barr Virus antibodies, it is not clear whether this is also true for gastric cancer. Potentially, these antibodies could serve as a noninvasive tool for gastric cancer screening or as markers for gastric cancer risk and provide a better understanding of the participation of Epstein-Barr Virus in the development of this neoplasm. Methods: We conducted a systematic review of articles analyzing anti-Epstein-Barr Virus serology in gastric cancer and precursor lesions following PRISMA guidelines. Patients were classified according to the Correa cascade of gastric lesions and whether they were positive or negative by EBER-in situ hybridization (Epstein-Barr Virus-associated gastric cancer and Epstein-Barr Virus-nonassociated gastric cancer, respectively). Results: We retrieved 16 articles involving 9735 subjects from 12 different countries and 4 databases, PubMed, SciELO, Scopus, and Google Scholar. Higher antibody titers were observed not only in Epstein-Barr Virus-associated gastric cancer than in Epstein-Barr Virus-nonassociated gastric cancer but also in Epstein-Barr Virus-nonassociated gastric cancer and gastric cancer-precursor lesions when compared with patients with mild dyspepsia or healthy controls. In all cases, the associations were predominantly with antibodies directed against lytic cycle antigens. Conclusion: Data support the role of Epstein-Barr Virus lytic reactivation in the development of advanced gastric lesions. However, more studies are needed to confirm these associations, particularly the association with lesions considered negative by EBER-in situ hybridization, and to establish a set of antibodies and thresholds indicative of enhanced risk to develop these lesions.

Urinary estrogen metabolites and gastric cancer risk among postmenopausal women.

BACKGROUND: The overall incidence of gastric cancer in women is half that in men for most global populations. Sex hormone pathways may be involved in carcinogenesis and estrogens have been postulated to protect women against gastric cancer. AIM: To evaluate associations of gastric cancer with estrogen metabolites in postmenopausal women. METHODS AND RESULTS: We performed an analysis of 233 gastric cancer cases and 281 age-matched controls from three prospective cohorts and two case-control studies of early-stage gastric cancer, mainly conducted in high-risk Asian populations. Fifteen estrogen-parent (estrone and estradiol) and -metabolite analytes (2-hydroxyestrone, 2-hydroxyestradiol, 2-hydroxyestrone-3-methyl ether, 4-hydroxyestrone; 4-methoxyestrone, 4-methoxyestradiol, 2-methoxyestrone, 2-methoxyestradiol, estriol, 16α-hydroxyestrone, 16-ketoestradiol, 16-epiestriol, and 17-epiestriol) were measured in spot urines using liquid chromatography-tandem mass spectrometry. Odds ratios for association with each marker were estimated by logistic regression. Heterogeneity was assessed by Cochran's Q test. Study-specific odds ratios were pooled by fixed-effects meta-analysis. Urinary levels of estrogen-related molecules were not associated with gastric cancer (adjusted odds ratios ranged from 0.87 to 1.27; p-values >.05), with low between-study heterogeneity (p-values >.1) for all but two metabolites (2-hydroxyestrone-3-methyl ether and 2-methoxyestradiol). CONCLUSION: To date, this is the first comprehensive assessment of endogenous estrogens with gastric cancer risk in women. Estrogens do not appear to have an etiologic role in gastric cancer risk among postmenopausal women. Given the complex network of sex steroid hormones and their extreme variation over the lifespan, further evaluation of this hypothesis is warranted.