D’Ambrosio et al. demonstrated that an ovarian cancer patient-derived xenograft (PDX) with the PIK3R1 mutation W624R was sensitive to the pan-class I PI3K inhibitor buparlisib, and also to the p110α specific inhibitor alpelisib, as well as to the dual PI3K and mTOR inhibitors dactolisib [52]. The gene discussed is PIK3CA; the disease is ovarian cancer.