Stomach cancer genetic factors

Genetic make-up is certainly a factor that predisposes an individual to cancer - a familial pattern of breast cancer is, for example, well-established. However, an additive and even predominant environmental effect is clearly evident when one studies migrant populations. In Japan, the incidence of stomach cancer is high, probably due to a high consumption of salted fish and pickled foods but the incidence of prostate cancer is low, perhaps because this has an association with the consumption of large amounts of red meat. However, in migrant Japanese communities in the USA, the incidence of these two cancers more closely mirrors that of the native US population, suggesting that the adopted US diet has affected their predisposition to the two cancers. In addition, black Americans have similar incidences of the main cancers to white Americans, but these differ markedly from those seen in black Africans. 

The pattern of H. pylori infection in the stomach leads to either increased or decreased acid secretion. Increased acid secretion predisposes to duodenal ulcer disease, whereas reduced secretion yields pangastritis and eventually gastric atrophy, precursors of gastric cancer. However, most infected individuals do not have clinically significant disease. The basis for these disparities is not clear, though vimlence factors of certain H. pylori strains and specific host genetic factors likely play a role. 

Cancer is a term commonly used for diseases in which abnormal cells divide uncontrollably and invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems. Cancer is not just one disease but many diseases. There are more than 100 different t3 pes of cancer, hence, the complexity of cancer treatment. It is the second leading cause of death worldwide after heart disease, and its risk and incidence increase with patient age (www. cancer.gov). In addition to genetic factors, enviromnental and nutritional factors play a main role in cancer etiology. In westernized countries, breast, prostate, and colon-rectum cancers predominate because diets are usually rich in animal-source foods and refined carbohydrates and deficient in plant foods. Conversely, in developing countries, where diets are largely based on cereal/starchy foods, esophageal, stomach, and liver cancers are more incident [127]. 

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