ESR1 and gastric cancer: Besides, ERα expression patterns varied in different GC patients, for example, the data from TCGA database (The Cancer Genome Atlas, https://tcga-data.nci.nih.gov/docs/publications/tcga/) showed that among 205 stomach adenocarcinoma samples, 5 samples were detected with ERα amplification, 1 with deep ERα deletion, and 6 with ERα mRNA upregulation.