E2F1 and cancer: At least two implications of these observations should be considered when translating the findings of this and similar studies to therapy designs: only MET-driven cancers, identified, for example, by the activation of the here-reported MET-E2F1-purine synthesis cascade (Fig. 7B), respond to MET targeting via small-molecule inhibitors, and METi can sensitize them to chemotherapies pending protocol optimizations.