“Stomach cancer is the fifth most common cancer worldwide. It is more common in countries in East Asia, Eastern Europe, and South and Central America than in the United States and other Western countries.  There are many known risk factors for stomach cancer (also called gastric cancer), but often it’s not clear exactly how these factors might affect how cells in the stomach become cancer cells. This is the subject of ongoing research.”

American Cancer Society (https://www.cancer.org/cancer/types/stomach-cancer/causes-risks-prevention/what-causes.html)