Analysis of 1918 patient samples from the TCGA database through cBioportal (http://www.cbioportal.org/) indicates that GATA3 expression was altered in 17% of the cases, these alterations are caused by gene amplification, mutation, deletion, and fusion, and among these, several missense and truncation mutations are considered to be potential driver mutations involved in breast cancer. The gene discussed is GATA3; the disease is breast cancer.