The stomach with atrophic gastritis can theoretically be considered to cause adenocarcinoma on the basis of "tissue distortion" that occurs between the mucosal epithelium and the lamina propria mucosae. This process can be divided into three steps. First of all, the stomach causes the relative difference in metabolic activity between the mucosal epithelium and the lamina propria mucosae. This relative difference in metabolic activity works as primary tissue distortion. Next, the stomach amplifies the tissue distortion by decreasing the momentum. Lastly, to neutralize the amplified tissue distortion, the stomach causes new tissue distortion at the peak of the amplified tissue distortion. This new tissue distortion has the ability to transform its own containing cells into cancer cells; in addition, it arises from the mucosal epithelium nearby the lamina propria mucosae. Thus, adenocarcinoma occurs in there: the mucosal epithelium nearby the lamina propria mucosae. Importantly, besides the stomach, other hollow organs such as the bronchus, the esophagus, the gallbladder, the large intestine, the urinary bladder, the vagina and so on, can also be considered to cause cancer almost by the same mechanism: the relative difference in metabolic activity among the layers.