Serum IgG Antibody against Helicobacter pylori and the CagA-VacA s1 Genotype as a Predictor of Gastric Cancer Development: A Case-control Study

Helicobacter pylori (H. pylori)-induced inflammation increases the risk of developing various upper gastrointestinal conditions which may progress to gastric cancer (CA). Early prediction and detection of infection are crucial for reducing cancer-induced mortality rates. The present case-control study aimed to investigate the combination of serum and molecular markers and H. pylori-associated gastro-duodenal conditions as risk factors for predicting CA development in dyspeptic patients. Consecutive gastric biopsies and blood samples were collected from 100 adult dyspeptic patients. Serum IgG antibody levels against H. pylori were determined, and receiver operating characteristic (ROC) analysis was performed. The expression of the virulence genes cagA and vacA was evaluated by polymerase chain reaction (PCR). A significant association was reported between the disease condition and the status of several risk factors, such as family history, serum IgG antibody concentration, and the virulence genes cagA and vacA. Among the 71 H. pylori-positive patients, 35.2% (25/71) had CA. Both cagA and vacA genes were found in 46 out of 71 (64.7%) patients, and 92% (23/25) of CA patients carried the cagA+vacA s1 gene. ROC analysis of the serum IgG concentrations revealed AUC values of 0.81 and 0.78 for differentiating patients with non-ulcer dyspepsia from those with ulceration/inflammation and CA, respectively. The concordance between the IgG-positive and PCR-positive patients was 84% (k value=0.41). Patients who had a family history of CA with an increased serum IgG concentration and the presence of H. pylori cagA-vacA s1 genotypes may be considered strong predictors of future development of gastric pathologies, including CA.