EGFR and non-small cell lung carcinoma: In this study, we developed a novel cohort of EGFR-mutant NSCLC patient-derived xenograft (PDX) models with heterogenous MET pathway activation, and evaluated osimertinib and savolitinib combination treatment in vivo to address the following questions: (i) What are the optimal MET assays to determine efficacy of osimertinib and savolitinib combination?