Allium vegetables, green tea, genetic susceptibilities, COX-2 and stomach cancer

Although the incidence of stomach cancer has been declining, it remains the second leading cause of cancer death worldwide. Nonetheless, little is known about potential gene-environmental interactions in stomach cancer development. The current study evaluates the relationships between stomach cancer and the following factors: allium vegetable intake, green tea drinking, genetic susceptibility, and cyclooxygenase-2 (COX-2). A population-based, case-control study conducted in China was used to evaluate the role of consumption of allium vegetables (e.g., garlic and onions) in stomach cancer risk. A second population-based, case-control study conducted in China was used to evaluate the role of green tea drinking and genetic susceptibility (polymorphisms GSTM1, GSTT1, GSTP1 and CYP2E1) in stomach cancer risk. Lastly, a hospital-based, case-control study conducted in New York was employed to evaluate the role of COX-2 and its potential link with environmental factors in stomach cancer development.; In the first study, results support an inverse relationship between allium vegetable intake and stomach cancer risk. In the second study, green tea drinking was found to be protective against both stomach cancer and chronic gastritis in Chinese population. Furthermore, our observations suggest that genetic polymorphisms of GSTM1, GSTT1, GSTP1 and CYP2E1 may not be independently associated with stomach cancer risk. However, potential gene-environmental interactions are indicated between smoking and GSTs, as well as between smoking, pickled food and CYP2E1. In the third study, expression of COX-2 was elevated in stomach cancer and its premalignant lesions, which suggests that COX-2 may be involved in the pathogenesis of this cancer.; In conclusion, clinical trials are suggested to explore the possibility of using garlic or onions as a low-cost remedy to reduce stomach cancer incidence. Intervention programs are indicated utilizing green tea for individuals in the early phase of stomach carcinogenesis, especially in high-risk populations. In addition, future studies of genetic polymorphisms should have a greater number of subjects and should incorporate environmental factors to better evaluate gene-environmental interactions on the risk of stomach cancer. COX-2 may have potential as an early marker for stomach cancer detection, and its inhibitors may be used to halt stomach cancer progression.