| Objective: Esophageal cancer in esophageal epithelial tissue is one kindof devastating diseases, which ranks the8th of the most common malignanttumors in the world. Every year it has about500000new cases, accounting for2%of all malignant tumors. In China, the incidence of esophageal carcinomahas distinct geographic aggregation, with high morbidity and high mortalityrelatively concentrated in certain areas, especially in Cixian of Hebei Provincewhere the incidence rate is up to103.5/100,000. There are numerousassociated triggering factors, including nitrosamines, mycotoxin and so on. Asis known to all, p53gene is suppressor genes. P53gene mutations can befound in more than half of the human tumor tissue, and the incidence of whichis obviously higher in esophageal cancer patients. The function and structureof P53are susceptible to the influence of gene polymorphism sites, which isrelated with the susceptibility of the tumor. According to the current research,the4th exon located in p53gene controls the growth and apoptosis of the cells.The N-terminal part of p53gene contains a Proline-rich region Pro, which is anecessary area where p53regulates the cell apoptosis, inhibits the tumorgrowth and reduces the level of E6factor. This area contains five SH3-bindingPXXP motifs, which may have a physical effect on some factors of signaltransduction pathways. When Arg located in the72th codon of p53geneinstead of Pro, one PXXP motif will be removed. This increases the instabilityof p53, resulting in a strong linkage disequilibrium in the72th codonpolymorphism. Therefore, we selected the72th codon as research sites. Acomparative analysis was designed in the study of the distribution of the p53fourth exon72th codon Arg/Pro polymorphism in esophageal carcinomapatients and normal people in Hebei Province. At the same time, we will investigate the associated factors leading to esophageal cancer. The researchabove will Provide some basis for prevention of esophageal cancer andinvestigation of its pathogenesis.Methods:1Basic research method: case-control study.2Specimen: The case group: esophageal cancer tissue is taken fromsurgical resection specimens of the50new cases patients of esophageal cancertreated in the Fourth Affiliated Hospital of Hebei Medical University duringthe period from November,2010to November,2011. Control group:50casesof normal tissues are taken from the same region in healthy individuals.3Biopsy specimens are obtained from patients and the slice excised fromthe typical position will be placed in RNA later solution and rapidly frozen.The known risk factors of esophageal cancer, such as smoking, drinking, drugabuse, diet, and external exposure factors including sawdust, industrial paints,and so on will be taken in detail through questionnaires. With the consentsobtaining from patients or their families, the fresh tissues of esophagealsquamous cell carcinoma and normal esophageal mucosa will be resected in asterile operating environment.4Tissue DNA extraction: DNA is extracted from tissue by using theQiagen, DNA columns Kit.5P53codon72polymorphism detection: Arg and Pro alleles areamplified by PCR according to the Arg/Pro nucleotide sequence primers ofP534th exon Codon72. Respectively, two pairs of primers are employed fordetection of two alleles by two parallel PCR. PCR reaction is performed inPCR amplification of AB company. Arg homozygotes generate a fragment inapProximately140bp, Pro homozygotes generate a fragment in about180bpand heterozygous Arg/Pro, respectively, Produce the above two fragments.Then, we calculate the genotype and the genotype frequencies will be detectedby the χ~2test, which has a significant test level of0.05.6An elaborate survey is conducted in esophageal cancer and controlgroups by questionnaires and data is analyzed to find out the relevant factors of esophageal cancer.Results:1The gene frequency of esophageal squamous cell carcinoma and controlgroups was tested by Hardy-weibridge equilibrium test and there was nosignificant difference between the case group and the control group (p>0.05).2Among the esophageal cancer patients in Hebei, the genotype frequencyof Arg/Arg was20%, Arg/Pro genotype frequency was20%and Pro/Progenotype frequency was10%. The control group genotype frequencies were12%,52%,36%, respectively. Compared with case group, the significantdifference existed (χ~2=10.607, P <0.05)3In Hebei,50cases of esophageal squamous cell carcinoma patients and50healthy control patients were investigated by case-control study throughquestionnaires. By logistic regression analysis, the expected incidence is48among the50esophageal cancer patients, which has the correct rate of96%(48/50) and the expected incidence is43among the50healthy people, whichhas the correct rate of86%(43/50). The total accuracy rate of the equationwas91%(91/100). The independent variables involved in the regressionequation are"drink, smoking, hot drinks, the living environments and familytumor history." Chi-square test result: χ2=98.879, p=0.000Thisequation is statistically significant. The regression equation: Logit P=-26.636+2.095living environment+21.128drink+3.357smoking+3.880hot drink-1.818tumor history.In this study, the influence of above four risk factors on p/(1-p) isrepresented by Logistic regression coefficient of five risk factors. The drinkodds ratio of esophageal cancer is1E+0.09, smoking is28.708, hot drink is48.401, the living environment is8.128and the family tumor history is0.162.Conclusions:1Though the results of this study, the polymorphism of P534th exonCodon72Arg/Pro is associated with the susceptibility to esophagealsquamous cell carcinoma in Hebei.2According to the analysis of the logistic regression equation, the risk factors of esophageal squamous cell carcinoma in Hebei are drink, smoking,hot drinks, living environments and family tumor history. |
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