ESR1 and breast cancer: To decipher the genetic differences between breast tumors from East Asian and Western patients, we proceeded to compare the CNV profiles of the NTUH discovery cohort with those of the METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) dataset.17 The cases were categorized into eight subgroups by age/ER/HER2 status (age: <50 years, ≥50 years; ER+, ER–; and HER2+; HER2–).