Etiology of gastric cancer – knowledge of modern medicine

By | April 3, 2012

From an analysis of domestic and foreign research data, cancer incidence and dietary factors, lifestyle and geography, and other relevant genetic factors. Among them, dietary factors, lifestyle, geographical environment as external factors, genetic factors are internal factors.
Common causes of gastric cancer 1. External causes: the Japanese immigrants to the United States research, the first generation of significantly decreased the incidence of dollars, suggesting that exposure from an early age pathogenic factor in the pathogenesis of this disease is very important. Because the stomach constantly in contact with food, it is believed that the substance present in food. As for what kind of material is not fully understood. Epidemiological investigations revealed that the system of gastric cancer and eat more fat foods such as sauerkraut, salted fish, bacon, and smoked foods, and even eat more starch was also made with the closely related substances. On the contrary, milk, fresh vegetables, fruit, vitamin C, and frozen foods can reduce the risk of gastric cancer. Excessive salt intake and gastric cancer incidence may be related to survey endemic areas, the patient most of the daily amount of salt intake over l0g.
Carcinogens cause cancer nitrite may be plastic. The lack of conclusive evidence yet of human gastric cancer, but animal experiments have proved it could be caused by stomach cancer. Plastic nitrite from nitrate reduction to nitrite and then with plastic combination. Widespread among nitrate in food may be nitrate-reducing bacteria in the stomach into nitrite. Nitrite is also widely present in foods, especially pickles, salted fish, bacon, etc., but its main source of nitrate reduction may come from. From gastric cancer often developed from chronic atrophic gastritis.
The latter benefit more from lower acid nitrate-reducing bacteria colonization of the Min. In high-prone areas (such as northwest China) have proved that the nitrate content in soil and high water; Also in the gastric juice of patients also demonstrated the presence of high concentrations of nitrite. Reducing salt intake is often accompanied by intake of nitrate and nitrite reduction. Low temperature can inhibit the nitrate into nitrite. United States, Japan and other countries in recent years, the decline in the incidence of gastric cancer, the extensive application of the refrigerator may be a factor. Vitamin C can inhibit the combination of nitrite and glue. In endemic areas has proved that long-term use of vitamin C in the population, the incidence of gastric vitamin C was significantly lower than those against. Although these observations provide only limited evidence to support the cause of human gastric nitrite rubber, but may be quite significant.
Common cause of cancer 2. Internal: Genetic factors and the incidence of gastric cancer have a close relationship. Gregorio and other research in Italy, Poland, Britain, Germany and Portugal-born immigrants Connecticut cancer incidence, with the American-born compared to local residents and found that stomach cancer mortality rates of these immigrants are higher than U.S. residents, suffering from stomach cancer risk 1.62_4.27 times higher, but the risk of gastric cancer than the country of birth of residents by 25% _64%. Haenszel Japanese immigrants in Hawaii and other observations found that high incidence of gastric cancer in Japan from the second generation of immigrants to the United States more than half of gastric cancer mortality. By pathological type further found that mortality was mainly due to intestinal type gastric cancer deaths dropped, while the diffuse type of gastric cancer deaths unchanged. These results suggest that two different types of gastric cancer by environmental and genetic factors are different. Dgowa other studies in Japan found that in 2848 cases of gastric cancer, gastric cancer relatives, 16.5%, 1.63 times higher than in other cancers, there are significant differences.
Further analysis showed that the brothers and sisters together gastric cancer is higher than the parents. The researchers think this is the time during which the child's living environment and the result of genetic factors. Zanghi 1986_1987 a region of Italy took place two years to investigate all cases of gastric cancer was found in patients with first-degree relatives of gastric cancer gastric cancer 2 times higher than the control group, relative risk 3.14, in the case of brothers and sisters in the relative risk was 4.33 ( P <O.02), while the incidence of gastric cancer patients and their parents no significant difference between the control group. Comparison by type of cancer found in relatives of patients with diffuse type gastric cancer was higher than in relatives of patients with intestinal type gastric cancer. These studies shows clustering of gastric cancer patients with a family. Is suffering from cancer susceptibility and environmental factors result of the role. In addition, patients with gastric cancer through the distribution of ABO blood group studies have shown that, A high incidence of blood type to the other Type III, and that undifferentiated gastric cancer histological type of blood type A patients were in the majority.
In addition, immunocompromised people a higher incidence of gastric cancer may be immune dysfunction, the role of reduced immune surveillance of cancer in gastric cancer have a certain significance.
Common causes of gastric cancer, and some scholars believe that environmental factors may have a relationship with gastric cancer, high and low latitude climate zones and climate zones of the distribution, directly affect the human living environment, while high latitudes may lack fresh fruits and vegetables, the other Geochemical considerations factors on human health. Addition of peat soil, coal or asbestos area residents and workers in metal, foundry workers, blacksmith, gas workers and workers exposed to sand and dust have a higher incidence of gastric cancer.
The relationship between trace elements and cancer incidence studies in recent years caused many concerns. Generally believed that the Ming, dry, lung, hammer, lead, bowls and other trace elements to be carcinogenic or cancer-promoting effect. Epidemiological studies of cancer indicate that diet In chains stopped the incidence of gastric contents were positively correlated, sprinkle able to inhibit certain cancer-causing effect. Vehicles can not only weaken the body's lack of tumor suppressor role, and can reduce immune function, so that decreased NK cell killing ability.

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