Progression of precancerous gastric lesions.
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Biomedical subjects
Publications and source records attributed to W C You.
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BACKGROUND: Stomach cancer is generally thought to evolve through a series of gastric mucosal changes, but the determinants of the precancerous lesions are not well understood. PURPOSE: Our purpose was to assess risk factors for intestinal metaplasia and gastric dysplasia arising from chronic atrophic gastritis in a general population at high risk for stomach cancer. METHODS: A population-based gastroscopic screening of more than 3000 residents was conducted in a county in China with one of the world's highest rates of stomach cancer. Information on the lifestyle and other characteristics of the participants was obtained by interview, and responses were compared between those in whom the most advanced gastric lesion was dysplasia or intestinal metaplasia versus those with chronic atrophic gastritis. RESULTS: Cigarette smoking was found to nearly double the risk of transition to dysplasia and to be a mild risk factor for intestinal metaplasia. Smoking accounted almost entirely for the 55% higher prevalence of dysplasia among men than among women. Risk of transition to dysplasia had a weak association with several dietary factors and was increased among those participants with a family history of stomach cancer and with blood type A. CONCLUSIONS: The findings provide strong evidence for a role of tobacco consumption and offer clues to other environmental and genetic factors involved in the process of gastric carcinogenesis.
The anatomic distribution of precancerous gastric lesions among 3,400 residents in Linqu, Shandong Province of China, was compared with the anatomic distribution of stomach cancer (SC) among 959 patients in Tokyo, Japan. The incidence of SC is high in both areas, and locations within the stomach of the precancerous and malignant lesions were classified using similar criteria. Chronic atrophic gastritis (CAG) affected 98% of the population in Linqu, with intestinal metaplasia (IM) the most severe diagnosis in 33% and dysplasia (DYS) in 20%. Neither the SC nor precancerous lesions were uniformly distributed in the stomach. Among the DYS 3% were along the greater curvature of the body, 15% along the lesser curvature of the body, 25% in the angulus, 22% along the lesser curvature of the antrum, and 34% elsewhere in the antrum. Among the SC the corresponding percentages were 2, 16, 28, 25 and 29. The similarity to the SC distribution increased gradually from CAG to IM to DYS, providing further evidence for the multistage progression of precancerous gastric lesions.
Research over the past several years in an area of Shandong, China, with one of the world's highest rates of gastric cancer, has yielded clues to the environmental determinants of this tumour. Interviews with 564 gastric cancer patients and 1131 population-based controls revealed increased risks associated with consumption of sour pancakes, a fermented staple unique to the area, in samples of which volatile N-nitrosamines have been detected. Lower risks were found among people who had a higher intake of fresh vegetables, including garlic and other Allium vegetables which contain constituents that can inhibit carcinogenesis by N-nitrosamines and other substances in experimental animals. A pilot study involving assays of urine and gastric juice from 60 individuals in a screening programme showed higher levels of N-nitrosoproline and of cis- and trans-N-nitroso-2-methylthiazolidine 4-carboxylic acid among persons with gastric dysplasia than in either normal controls or those with chronic atrophic gastritis. We are trying to characterize the transition and progression of precursor lesions to gastric cancer and to evaluate the role of dietary variables, nutrients, N-nitroso compounds and other factors in particular stages of the carcinogenic process.
Endoscopic and pathologic examinations were conducted in a randomly chosen population in a high risk area of gastric cancer, Linqu County, Shandong Province. A high prevalence of chronic atrophic gastritis, intestinal metaplasia and dysplasia was found. Gastric mucosal lesions changed from mild to severe with a decline in transition rate. The prevalence rate of severe dysplasia was close to that of gastric cancer. The study indicates that gastric precancerous lesions are related to malignant changes implying that gastric cancer develops on the damaged gastric mucosa. It is also shown that the progression from chronic atrophic gastritis to dysplasia may take an average of 20 years.
Interviews with 564 patients with stomach cancer and 1,131 controls in an area of China where gastric cancer rates are high revealed a significant reduction in gastric cancer risk with increasing consumption of allium vegetables. Persons in the highest quartile of intake experienced only 40% of the risk of those in the lowest. Protective effects were seen for garlic, onions, and other allium foods. Although additional research is needed before etiologic inferences can be made, the findings are consistent with recent reports of tumor inhibition following administration of allium compounds in experimental animals.
A case-control investigation involving interviews with 564 stomach cancer patients and 1131 population-based controls was conducted to evaluate reasons for the exceptionally high rates of stomach cancer in Linqu, a rural county in Shandong Province in northeast China. Daily consumption of sour pancakes, a fermented indigenous staple, was associated with a 30% increase in risk. Risks of stomach cancer were also increased by 2- to 3-fold among persons with prior chronic gastritis or gastric ulcer, by 80% among those with stomach cancer in a family member, by 50% among men who smoked one or more packs of cigarettes/day, by 40% among those who preferred salty foods, and by 50% among families with moldy grain supplies. In contrast, risks tended to decrease in proportion to increasing consumption of fresh vegetables and fruits. This protective effect was more pronounced for vegetables, with those in the highest quartile of intake at less than one-half the risk of those in the lowest. Stomach cancer risks also declined with increasing dietary intake of carotene, vitamin C, and calcium, but not retinol. These findings provide leads to dietary factors that contribute to the high rates in Linqu, where stomach cancer is the leading cause of cancer and has not yet begun to decline as in other parts of the world.
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The corresponding antigen to monoclonal antibody PCI against gastric cancer cells was demonstrated as a protein sensitive to heating and easily degraded by proteinase. By western blotting, it was shown that the molecular weight of the antigen was 42 KD and the antigen was named P42. P42 could be shed into serum-free culture medium of the target cells and its activity be assayed in sera of the gastric cancer patients. Using inhibition test, the levels of P42-like substance in sera were measured. The results indicated that this level in the gastric cancer patients (26.53 +/- 23.11) was markedly higher than that in patients with benign gastric diseases (4.66 +/- 2.67) and controls (2.57 +/- 2.67). It is suggested that P42, a novel gastric cancer-associated antigen, be useful in the mass screening and supplementary in diagnosing gastric cancer.
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Stomach cancer is the leading cause of death from cancer in China. Although the causes of this cancer are unknown, special opportunities exist for the evaluation of etiologic factors in Linqu County in Shandong Province where rates are exceptionally high. We have described here a newly initiated case-control study, which focuses on certain dietary items as risk factors for stomach cancer in Linqu.
The problem of chemically contaminated water supplies are in general terms followed by a description of three examples of water supply problems in China. A large-scale prospective epidemiological study, now in the early planning stages, to be carried out in China is also described.