Effects of the CYP2C19 Genetic Polymorphism on Gastritis, Peptic Ulcer Disease, Peptic Ulcer Bleeding and Gastric Cancer

Background: The CYP2C19 genotype has been found to be an important factor for peptic ulcer healing and H. pylori eradication, influencing the efficacy of proton pump inhibitors (PPIs) and the pathogenesis of gastric cancer. The aim of this study was to investigate clinical correlations of the CYP2C19 genotype in patients with gastritis, peptic ulcer disease (PUD), peptic ulcer bleeding (PUB) and gastric cancer in Thailand. Materials and Methods: Clinical information, endoscopic findings and H. pylori infection status of patients were assessed between May 2012 and November 2014 in Thammasat University Hospital, Thailand. Upper GI endoscopy was performed for all patients. Five milliliters of blood were collected for H. pylori serological diagnosis and CYP2C19 study. CYP2C19 genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (RFLP) and classified as rapid metabolizer (RM), intermediate metabolizer (IM) or poor metabolizer (PM). Results: A total of 202 patients were enrolled including 114 with gastritis, 36 with PUD, 50 with PUB and 2 with gastric cancer. Prevalence of CYP2C19 genotype was 82/202 (40.6%) in RM, 99/202 (49%) in IM and 21/202 (10.4%) in PM. Overall H. pylori infection was 138/202 patients (68.3%). H. pylori infection was demonstrated in 72% in RM genotype, 69.7% in IM genotype and 47.6% in PM genotype. Both gastric cancer patients had the IM genotype. In PUB patients, the prevalence of genotype RM (56%) was highest followed by IM (32%) and PM(12%). Furthermore, the prevalence of genotype RM in PUB was significantly greater than gastritis patients (56% vs 36%: p=0.016; OR=2.3, 95% CI=1.1-4.7). Conclusions: CYP2C19 genotype IM was the most common genotype whereas genotype RM was the most common in PUB patients. All gastric cancer patients had genotype IM. The CYP2C19 genotype RM might be play role in development of PUD and PUB. Further study in different population is necessary to verify clinical usefulness of CYP2C19 genotyping in development of these upper GI diseases.