In order to extend the knowledge, we assessed the prevalence of the E542K, E545K, H1047R mutations within the PIK3CA gene and the E17K mutation within the AKT1 gene, and the expression of the PIK3CA, PIK3R1, PTEN, AKT1, mTOR genes in a cohort of patients with breast cancer. This evidence concerns the gene PIK3R1 and breast carcinoma.