[Effects of Yanting diet and vitamins on growth and proliferation of human esophageal cancer cell line].

OBJECTIVE: The effects of sera of rats fed the Yanting diet (YT diet) on growth and proliferation of the human esophageal cancer cell line Eca-109 were observed by the means of sero-physiology. METHODS: The male SD rats, randomly divided into six groups with ten each, were fed a conventional diet and five experimental diets, i.e. YT diet, the YT diet with two vitamin mixtures (Mix. 1, vit. A, E and folic acid; Mix. 2 was Mix. 1 plus riboflavin and vit. C) at two doses. After rats fed different diets for 30 days, rats' sera were collected and added into medium for cell culture. The effects serum of rats fed different diets on two human cell lines (Eca-109 esophageal cancer cell and HL7702 normal liver epithelium cell) were investigated by means of cell growth curve, 3H-thymidine incorporation and flow cytometric assay. RESULTS: By comparison with the control, the sera of rats fed the YT diet significantly promoted Eca-109 cell proliferation but showed inhibitory effects on HL7702 cell. These changes, however, were reversed by supplementation with two vitamin mixtures at high dose, which had more significant effects on either inhibiting Eca-109 cell or promoting HL7702 cell proliferation than the corresponding lower dose. In addition, the high dose of two vitamin mixtures caused G1 arrest of Eca-109 cell, while speeding the HL7702 cell entering into S and G2 of cell cycle. No obvious difference was seen between both serum of rat fed with the conventional diet and calf serum as control to effect on the two cell line growths and proliferations. CONCLUSION: It is indicated that the sera of rats fed with the YT diet could promote the proliferation of human esophageal cancer cell line Eca-109; the YT diet supplemented with vitamin mixtures may have inhibitory effects on Eca-109 cell. The cell cycle arrest of G1 may be one of the mechanisms that the YT diet supplemented with vitamin mixtures inhibited the proliferation of Eca-109 cell.

Risk factors for esophageal cancer: a case-control study in South-western China.

Esophageal cancer is a crucial cancer in China. Yanting in Sichuan Province was a key area with highest esophageal cancer mortality in China, but little evidence on esophageal cancer risk factors has been reported for this area and the etiology remains unclear. To clarify risk factors, a 1:1 matched case-control study was conducted. Totals of 185 eligible esophageal cancer patients and 185 healthy residents matched for sex and age were recruited. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for possible risk/protective factors. All ORs were adjusted by family history of esophageal cancer and occupation, and then further adjusted by other possible confounding factors. Our results showed that smoking and alcohol drinking were risk factors for esophageal cancer with dose-response. The ORs (95% CI) compared with never smokers and drinkers were 4.06 (1.55-10.6) and 2.49 (1.06-5.85), respectively. The OR was further increased to 8.86 (95% CI, 3.82-20.5) for both smoking and drinking in combination. Eating food rapidly (OR=5.84, 95% CI, 2.05-16.7), drinking shallow ground water (OR=4.18, 95% CI, 1.30-13.4) and frequent intake of picked vegetables (OR=2.12, 95% CI, 1.00-4.49) appeared to increase the risk, while frequent intake of fresh fruit (OR=0.42, 95% CI, 0.19-0.89), fresh vegetables (OR= 0.62, 95% CI, 0.32-1.17) and eggs (OR=0.59, 95% CI, 0.25-1.39) decreased the risk. In conclusion, smoking and alcohol drinking are common in Yanting and main contributors to esophageal cancer. Consumption of fresh fruit and eggs are not common and high consumption of these two foods as well as fresh vegetables may decrease the risk of esophageal cancer in this area. In addition, drinking shallow ground water and eating food rapidly, as well as frequent intake of pickled vegetables, are also factors increasing the risk.