P1.095. International Collaborative Study on the Relationship Between ALDH2 Gene Polymorphism and Changes in Salivary Acetaldehyde Concentration by L8020 Lactobacillus

Abstract

Abstract Topic Esophageal Cancer: Esophageal Carcinogenesis Background Seventy-five percent of the world's esophageal cancer cases occur in Asia. The primary cause is the presence of the flasher (ALDH2 non-inactivating type). The ALDH2 gene polymorphism (rs671 G>A) is believed to have originated in China 2,000 to 3,000 years ago. While the non-inactivating genotype is limited to Asians, it has been shown to account for 8% of the global population (approximately 540 million people). Methods Our series of clinical and basic research findings on the oral environment of esophageal cancer patients has shown that “creating an oral environment dominated by beneficial bacteria rather than periodontal bacteria” may not only reduce postoperative complications but also decrease postoperative recurrence, improve prognosis, and potentially lower the risk of esophageal cancer itself. It was at this juncture, while contemplating how to efficiently create an oral environment dominated by beneficial bacteria rather than periodontal bacteria, that we discovered oral care products containing L8020 lactic acid bacteria. Professor Hiroki Nikawa of Hiroshima University, prompted by the question “Why do some people avoid cavities and periodontal disease even without brushing their teeth?”, isolated 42 types of lactic acid bacteria from the oral cavities of 13 such individuals. Among these, Lactobacillus rhamnosus (KO3 strain), which exhibited the strongest antibacterial activity against cariogenic and periodontal pathogens, was named L8020 lactic acid bacteria. Results At the 79th Annual Meeting of the Japanese Society for Esophageal Diseases in June 2025, the results of this research series were presented at an English symposium. Following this, Professor Che-Hong Chen of Stanford University proposed an international collaborative study. This report outlines the background of an international collaborative study involving Akita University, National Kaohsiung University of Science and Technology (Taiwan), and Stanford University (USA). Conclusion The study investigates whether oral care products containing L8020 lactic acid bacteria can reduce acetaldehyde concentrations in saliva and thereby lower the risk of multiple diseases, including esophageal cancer.