Precancerous diseases of the stomach. Risk Groups

It is generally accepted that gastric cancer is preceded by a number of natural diseases that are characterized as precancer. In 1978 the WHO Expert Committee on the study of pre-cancerous gastric recommended to provide pre-cancerous condition (optional precancer) and pre-cancerous changes - dysplasia (obligate precancer).
By precancerous conditions include: 
chronic gastritis of various etiologies, including autoimmune gastritis type A, accompanied by pernicious anemia; adenomatous polyps of the stomach; chronic gastric ulcer; resected stomach for benign disease; Menetries disease. Chronic gastritis (some researchers consider it as gastropathy as atrophic and proliferative processes prevail over the inflammatory) precedes the appearance of stomach cancer in 73,5-85% of cases. Chronic gastritis - polietiologic disease, and depending on the etiological factor, there are six types of chronic gastritis:
Type A - autoimmune, mainly affects the body and the bottom of the stomach and is characterized by the appearance of antibodies to parietal cells type B - bacterial, caused by the bacteria Helicobacter pylori, Type AB - mixed; Type C - chemical, mainly reflux genesis; lymphocytic or varioliform - is characterized by severe lymphocytic infiltration of the epithelium of the ridges and hollows, the appearance of multiple small uzelkovidnyh growths in the mucous membrane and is regarded as a special form of immune response to H. pylori and how predlimfoma, special forms, which include other forms of infectious gastritis, including those caused by other than H. pylori, spiral bacteria, Helicobacter heilmannii (Gastrospirillum hominis).