ESR1 and carcinoma of esophagus: In the present study, we first explored the transcriptional levels of estrogen receptors (ESR1 and ESR2) and GPER1 RNA in esophageal carcinoma tissues by analyzing the data from GEPIA, which is a web-based tool to deliver fast and customizable functionalities based on The Cancer Genome Atlas (TCGA) and Genotype Tissue Expression project (GTEx) data [31].