Esophagogastric junction cancer and classification as esophagus cancer according to molecular fingerprint

4059Background: The 7th edition of UICC staging system moved GEJ cancers from gastric staging group to esophagus cancers. Since clinical management is strongly influenced by this staging system, we looked at molecular fingerprints of GEJ tumors and compared to gastric and esophagus profiles, to elucidate whether GEJ cluster in the gastric or esophagus cancer groups, according to mRNA expression pattern, since this might represent tumor identity. Methods: The clinical and expression data were downloaded from TCGA. The total number of samples was 1167 ( 450 stomach, 196 esophagus and 521 colon samples). Both Principal Component Analysis (PCA) and Heat Map (HM) plots were performed in R platform, using Log2 transformation of RPKM normalized data. Differential Expression Analysis was also performed in R, using RAW data and the DESeq2 package. Benjamini and Hochberg False Discovery Rate corrections were used. The mRNAs were tagged as differentially expressed if they met the following criteria: i) FDR adjusted ...