Interaction between environmental and genetic factors in the development of esophageal cancer

为了解我国食道癌高发区之一磁县食道癌发生的环境风险，以食道癌高、中、低发区居民404人、352人、400人以及301例食道癌患者为研究对象。对这些受试者进行了7天加权问卷的食物摄取频率调查。问卷还包括职业、工作条件、年收入、家族疾病史、抱怨和人口统计特征。对所选井水中的氮化合物水平在三个地区进行了测定。居住在三个不同地区的居民在食物摄入量上存在明显的差异，这表明营养风格存在地区差异。在男性和女性中，生活在…的居民对土豆、水果、蔬菜和肉类的摄入量都明显较低高发区居民比其他居民多，与癌症患者的情况大致相同。在食道癌高发区的人群中，胡萝卜素、维生素A和C的摄入量也较低。污染井水中含氮化合物与食道癌高发密切相关。相比之下，吸烟、饮酒、腌制蔬菜和霉变食物的摄入量与不同的发病率无关。这些结果提示水果、蔬菜、土豆和肉类的摄入量减少以及井水的水质可能是磁县食道癌发生的重要危险因素。对65例居住在磁县(中国)及其附近高发区的食道癌(食管鳞癌)进行了p53抑癌基因外显子5-8的突变分析。用聚合酶链式反应扩增鉴定突变。在65例样本中，40%的突变主要发生在外显子5和8。总的来说，没有p53突变的患者对几种食物的摄入量较低。特别是，无P53突变的患者的肉类摄入量显著低于有P53突变的患者。较少

The purpose of this study is to find out environmental risks for the development of esophageal cancer in Ci-Xian, where is one of the highest incidence area of esophageal cancer in China.Subjects were 404, 352 and 400 inhabitants living in high, medium and low incidence areas of esophageal cancer, as well as 301 esophageal patients. A food intake-frequency survey using the 7-day weighted inventory questionnaire was conducted for these subjects. Occupation, working condition, income per year, family history of diseases, complaints, and demographic features were also included in the questionnaire. The levels of nitrogen compound in selected well water were measured in each three area. Clear-cut differences in the intake of foods were seen among inhabitants living in the three different areas, suggesting that the regional differences in the nutritional style exist. In both males and females, the intakes of potatoes, fruit, vegetables and meat were significantly lower in inhabitants living … More in the high-incidence area than the other inhabitants, much the same as those of cancer patients. The lowered intakes of carotene, vitamin A and C were also seen in populations living in the high-incidence area of esophageal cancer. The polluted well water with nitrogen compounds was significantly related to the high incidence of esophageal cancer. In contrast, tobacco, alcohol consumption, and intake of pickled vegetable and moldy foods did not relate to the different incidence. These results suggest that the lowered intakes of fruit, vegetables, potatoes and meat, and quality of well water may be important risks for 'the development of esophageal cancer in Ci-Xian.Carcinomas of upper digestive tract (squamous-cell carcinoma of the esophagus) from 65 patients residing in Ci-Xian (China) and near-by high-incidence areas were analyzed for mutations in exons 5-8 of the p53 tumor-repressor gene. Mutations were identified by polymerase chain reaction amplification. Of 65 specimens, 40% had mutations mainly in exon 5 and 8. In general, patients without p53 mutations had lowered intake of several kinds of foods. Especially, the intake of meat was significantly lower in patients without p53 mutations than in those with p53 mutations. Less