ERBB2 and breast cancer: In metastatic HR+/HER2- breast cancer that has progressed after adjuvant endocrine therapy, a significant progression-free survival (PFS) benefit can be achieved in the context of PI3K/AKT pathway mutations when alpelesib [40], capivasertib [41], or inavolisib [42] is administered with fulvestrant (alpelesib and capivasertib) or with fulvestrant plus palbociclib (inavolisib).