For the analysis of the ERRα metabolic gene expression profile in breast cancer patients, we used the data obtained from the Gene Expression Omnibus (GEO) database to compare the basal-like breast tumours of overweight/obese versus lean patients, based on the premise that basal-like breast tumours are considered to be representative of the TNBC, a subtype for which there is no satisfactory treatment available. This evidence concerns the gene ESRRA and breast cancer.