PTEN and breast cancer: In AKT pathway-altered (PIK3CA, AKT1, or PTEN) HR-positive/HER2-negative advanced BC patients after progression under endocrine treatment, the CAPItelle 291 study showed a significant increase in PFS (7.3 months versus 3.1 months) using the AKT inhibitor capivasertib in combination with fulvestrant compared to placebo and fulvestrant [303].