Identification of genes associated with histologic tumor grade of esophageal squamous cell carcinoma

The present study aimed to identify the genes associated with the histologic tumor grade of patients with esophageal squamous cell carcinoma (ESCC) and to provide valuable information for the identification of potential diagnostic biomarkers in ESCC. Tumor samples of ESCC patients retrieved from The Cancer Genome Atlas were divided into Grade 1 (well‐differentiated; G1), Grade 2 (moderately‐differentiated; G2) and Grade 3 (poorly‐differentiated; G3) groups in accordance with the clinical record of the tumor grade of ESCC patients. The genes associated with tumor grade were identified. The signaling pathways of identified genes were enriched from the Kyoto Encyclopedia of Genes and Genomes (KEGG). The diagnostic value of candidate genes was assessed by receiver operating characteristic analysis. We used the GSE23400 dataset generated from the Gene Expression Omnibus to examine the expression levels of candidate genes in ESCC tissues compared to matched mucosa tissues. In total, 440 genes positively correlated with tumor grade and 882 genes negatively correlated with tumor grade were identified. There were 310 differentially expressed genes (DEGs) between G1 and G2, 184 DEGs between G2 and G3, and 710 DEGs between G1 and G3. There were 1322 genes associated with tumor grade that were significantly enriched in pathways in cancer and the phospholipase D signaling pathway. Cyclin‐dependent kinase inhibitor 1A, golgin A7 family member B and transforming growth factor B1‐induced anti‐apoptotic factor 1 (TIAF1) had potential diagnostic value for discriminating ESCC patients with G1 from those with G3. TIAF1 was significantly down‐regulated in ESCC. The results of the present study comprise useful groundwork with respect to determining the tumorigenesis mechanism in ESCC and discovering potential diagnostic biomarkers for ESCC.