Screening Of The Differential Expression Genes In Human Esophageal Squamous Cell Carcinoma And Adjacent Normal Tissues Using Gene Chip

BackgroundEsophageal cancer is one of the most common malignant tumors in our country. The incident rate of esophageal cancer in Linzhou is 150/100,000. Esophaeal cancer with strong invasion, rapid progress and poor prognosis is accompanied with lymph node metastasis, easy to relapse. Conventional surgery, radiotherapy and chemotherapy are the unpleasantness, so searching new methods for the treatment of esophageal cancer is the current research focus.Gene chip is also called the DNA microarray or oligonucleotide microarray, which is the development of a new DNA analysis technology after the 1990's. Gene chip is a new technology that a plenty of oligonucleotide microarray or genetic fragments are arranged in some solid-phase carrier (usually around 1cm2 slide, silicon wafer and nylon membrane) high-density and orderly to detect a particular gene expression. The basic principle of the test is bases complementary, molecular hybridization. A lot of probe molecules are immobilized on solid-phase holder, after that using fluorescent tags sequence or sample (DNA or cDNA) and chip probe hybrid. And then washing away the fragment did not happen complementary binding reaction from the solid-phase holder. At last, we can speculate a plenty of gene quantitative information about the sample through the confocal laser scanning microscopy and with the help of computer system to analyse the strength of the fluorescent signal.At present, nationally and internationally, using microarray technology screening of differentially expression genes of all kinds of tumor tissues has made some achievements, such as ovarian cancer, stomach etc.But only a few reports about esophageal cancer. This experiment analysed the gene expression situation of esophageal squamous cell carcinoma through gene chip technology, compared with the gene expression of normal esophageal mucosal tissue, to find out the genes differenttially expressed which related to the occurrence and development of esophageal squamous cell carcinoma.This can provide high specificity,sensitive molecular markers and target genes for the early diagnosis,prevention and treatment of esophageal squamous cell carcinoma.MethodsTotal mRNA was extracted from human esophageal squamous cell carcinoma and adjacent normal tissue and cDNA was acquired by reverse transcription reaction. Probe was made by cDNA which labeled with Cy3-dUTP from normal esophageal tissues and esophageal carcinoma, then hybridized with gene chip, scanned, the signal data acquired by software analysis and comparison, selected out genes different in expression.Using RT-PCR verify the Gene chip test results by another 30 cases of specimens.ResultsIn five cases of fresh specimens hybridized with gene chip, a total of 1113 different in gene expression was found, including 464 up-regulation, 649down-regulation. These genes were divided by molecular function (function term) according to GO(gene ontology) Category, the most of these genes are relevant to cell differentiation, maturation, molecular orientation, connectivity, signal transduction, enzyme activity regulation, as well as gene transcription and translation.Test and verify 3 genes of all by RT-PCR, which expression direction consistent with the results detected by gene chip, according with expected results. Conclusion1. There are lots of genes involved in the progression of ESCC;2.Using the microarray to screen the difference of gene expression profiles might be of benefit to rapid select the relative genes of the esophageal carcinoma.