The endocrine therapy is the new frontiers of many breast cancers hormone sensitive, linked to specific genetic alteration such as copy number aberrations (i.e., ERBB2, CCND1 amplification loci), homozygous deletions of CDKN2A/B and PTEN, and high-frequency substitution and insertion/deletion (indel) driver mutations in cancer genes like TP53 (~frequency 53%), PIK3CA (8–26%), CDH1 (21%), AKT1 (8%) and GATA3 (4%). Here, PTEN is linked to breast cancer.