Do we know what causes stomach cancer?
There are many known risk factors for stomach cancer, but no one knows exactly how these factors cause cells of the stomach lining to become cancerous. This is currently being investigated.
Several changes, which are precancerous think may occur in the lining of the stomach.
One of these is the atrophic gastritis, a condition in which the normal stomach glands have decreased or disappeared. In addition, there is some degree of inflammation (immune system cells damaged patient’s cells in the stomach) . Infection with H pylori often causes atrophic gastritis. No one knows exactly why this condition develops cancer.
Another change that could also be cancerous is the intestinal metaplasia, in which the normal lining of the stomach is replaced with cells that closely resemble the cells that normally line the intestine. People with this condition usually also have chronic atrophic gastritis. It is not known exactly how or why this change occurs and becomes stomach cancer. This could also be related to infection by Helicobacter pylori.
Recent research has provided some clues about how they form some stomach cancers. For example, the bacterium Helicobacter pylori, particularly certain subtypes can convert certain food substances into chemicals that cause mutations (changes) in the DNA of cells lining the stomach. This may also explain why certain foods such as preserved meats, increase a person’s risk of developing stomach cancer. Moreover, some foods that decrease the risk of stomach cancer contain antioxidants, which can block substances that damage the DNA of a cell.
In recent years, some scientists have made great progress in understanding how certain changes in DNA can cause normal stomach cells grow abnormally and form a cancer. DNA is the chemical in every cell that carries our genes (instructions on how our cells). Resemble our parents because they are the source of our DNA. However, DNA affects more than just our appearance.
Some genes contain instructions for controlling when cells must grow and divide. Certain genes that promote cell division are called oncogenes . Other conditions that cause cell division or cause cells to die at the right time are called tumor suppressor genes . Cancer can be caused by changes in DNA that activate oncogenes or inactivate tumor suppressor genes.
There are also genes that produce enzymes to repair DNA when it undergoes abnormal changes. If you lose or damage these genes, this may also result in cancer.
Inherited abnormalities of some of these types of genes (as explained in ” What are the risk factors for stomach cancer? “) can increase a person’s risk of developing stomach cancer. However, most genetic changes that lead to stomach cancer occurs after birth. Heritable genetic changes are responsible for only a small percentage of cancers of the stomach.