PIK3CA and neoplasm: In the CT-71 case, after 15 months of ribociclib-letrozole therapy resulting in the CR of the lymph node and SD of bone metastases, a slow elevation of PIK3CA H1047R occurred; this aberration could guide the therapy decision: when the progression of bone metastases was verified by means of a CT, bone scan, and tumor markers 3 months later, alpelisib-fulvestrant therapy was started.