How does stomach cancer grow and spread?

H pylori, gastritis: Infection by helicobacter pylori is believed to be the cause of most stomach cancer while autoimmune atrophic gastritis, intestinal metaplasia. There is a correlation between iodine deficiency or excess, iodine-deficient goitre and gastric cancer. Iodide ion can function in gastric mucosa as an antioxidant reducing species that can detoxify poisonous reactive oxygen species, like hydrogen peroxide.

Cancers: Cancer cells are abnormal cells that do not know when to stop growing and multiplying. Cancer cells can grow into a lump or mass, may outgrow their blood supply and break down, may ulcerate into the stomach and bleed, may grow outside the stomach wall & attach to other organs, may spread to lymph nodes or to other organs such as the liver.