Study finds unknown mutagen linked to stomach cancer

Researchers have discovered a potential new cause of stomach cancer in a recent study. Stomach cancer is the fifth most common cancer worldwide, with nearly one million new cases reported in 2022. It is also the third leading cause of cancer-related deaths globally. Scientists from the Wellcome Sanger Institute, Broad Institute of MIT and Harvard, and the University of Hong Kong studied stomach lining samples from individuals with and without gastric cancer. They sequenced the genomes of these samples to learn more about mutations that can lead to cancer. The research revealed that normal stomach lining cells have a mechanism that protects them from the acidic environment of the stomach. However, by age 60, nearly 10% of these cells can have “driver” mutations associated with cancer. An unusual finding was that some individuals had three copies of certain chromosomes, suggesting potential exposure to an unknown mutagen. The study analyzed 238 samples from 30 individuals, including 18 with gastric cancer. The researchers used advanced methods to pinpoint mutations in normal cells. They found that mutations in normal gastric cells occur at a rate similar to other body cells, indicating a protective effect. In individuals with gastric cancer, changes were observed in some normal cells, raising concerns that they could be transitioning toward cancer. The cancerous tissues showed significantly higher mutation rates compared to normal tissues. The findings raise questions about how chronic inflammation may increase the risk of stomach cancer. The researchers emphasize the importance of understanding these mutations to trace early stages of cancer development. Professors involved in the study highlighted the significance of exploring mutations in normal tissues. They noted that this research could open new avenues for studying not only stomach cancer but also other diseases triggered by mutations.