PTEN and breast cancer: Indeed, up to 50% of hormone receptor-positive (HR+) BC and about 25% of triple-negative BC (TNBC) present PI3K/AKT pathway hyperactivation, mainly sustained by PIK3CA point mutations in HR + tumors and by PTEN loss in TNBC (Stemke-Hale et al., 2008; Cancer Genome Atlas Network 2012; Pascual and Turner, 2019; Vasan et al., 2019).