PIK3CA and breast cancer: We then study the effect that the activation of an additional drug, as a model of multi-drug therapy on PIK3CA-mutant breast cancer cells, has on the long-term behavior of the dynamical system in order to determine which drugs best synergize with Alpelisib. As already shown by ref. 40, we find that only two drugs have significant impact on system dynamics in this context: Palbociclib and Fulvestrant.