PIK3CA and breast cancer: In metastatic breast cancer (MBC) patients, when PIK3CA mutation was detected in circulating tumour DNA, progression‐free survival (PFS) improvement became largely significant (Delaloge & DeForceville, 2017), and BYL‐719 (alpelisib) was recently granted marketing authorisation for the treatment of breast cancer in combination with endocrine therapy (André et al,2019).