Theonly patient with breast cancer treated with everolimus who experienced a complete response had a PIK3CA mutation (Glu545Lys), as well as a KRAS mutation (Ala146Thr), associated with heterozygous deletions in the ATM, BRCA2, CDH1, PTEN, RB1, SMAD4, and TP53 genes (Table 2 and Data Supplement). This evidence concerns the gene PIK3CA and breast cancer.