APOC1 and neoplasm: In this study, we applied several databases such as The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and the Genotype-Tissue Expression (GETx) (28-30); bioinformatics algorithms; and web tools such as the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) (31) and TISIDB(an integrated repository portal for tumor-immune system interactions) (32) to analyze the correlation between APOC1 and the tumor microenvironment of ESCA and to clarify the diagnostic and prognostic value, tumorigenic mechanism, and immune response regulation of APOC1 in ESCA.