Gastric cancer is the fifth most common malignancy worldwide and the third in mortality. In 2010, UICC released the latest edition of the TNM staging manual in the adenocarcinoma esophageal-gastric junction (JEG) with epicenter at 5 cm from the JEG and extending into the esophagus is classified and staged together with the esophageal tumors, while those that do not extend into the esophagus remain classified and staged as gastric adenocarcinoma. This change was due to differences between adenocarcinomas of the JEG and stomach, risk factors, treatment and prognosis. With the development of molecular biology, several areas - such as transcriptomics, studying gene expression on a genomic scale - started to be used to explore differences in expression in various tumor types. In this sense, the Atlas Genomic Cancer (TCGA) is a database that aims to generate complete maps of the genomic key changes of the major types of cancer, in order to accelerate the understanding of the molecular basis of cancer through the application of technology genome analysis, which makes it a powerful tool in this area. Considering these aspects, the aim of this study is to comparatively analyze the transcriptome of adenocarcinomas of the JEG and gastric using TCGA data as a tool for validation. To this end, the gastrectomy at the University Hospital João de Barros Barreto eight patients samples were obtained submitted, four adenocarcinomas of the JEG and four gastric adenocarcinomas. Samples were analyzed using the technique of expression microarray chips with Human Gene 1.0 ST Array (Affymetrix®) which allow the analysis of 36,079 transcripts. The transcriptome analysis revealed 36 genes differentially expressed (fold-change greater than or equal to 5), 11 and 25 hipoexpressos hiperexpressos genes in JEG adenocarcinoma in relation to gastric adenocarcinomas. In the analysis of TCGA were identified 509 differentially expressed genes (p <0.05), and the ASPN genes, LiPF HNRNPM and validated for this database. Thus, it is concluded that the differential gene analysis shows significant changes between gastric adenocarccinoma and JEG and its molecular differences may reflect the clinical features, stressing that these tumors should be classified and staged differently.
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