To examine in more depth the prevalence of co-occurring alterations in PIK3CA and PTEN in ER+ BC three different datasets were analysed: METABRIC (Molecular Taxonomy of Breast Cancer International Consortium)19,20, TCGA (The Cancer Genome Atlas)21 and TEMPUS (https://www.tempus.com/) (Fig. 1A). This evidence concerns the gene PIK3CA and breast cancer.