Noteworthy, the efficacy of combinations of ET with mTOR, PI3K, and CDK4/6 inhibitors, the biological interplay between these pathways and the sensitization of cancer mutant cells led to the design of clinical studies investigating triplet combinations [[2], [3], [4], [5],22,23,[35], [36], [37], [38]]. The gene discussed is PIK3CA; the disease is cancer.