MET and acute myeloid leukemia: As expected, LiCl also showed strong activity (10–20 mM is a widely used concentration relevant for GSK3 inhibition by LiCl5, which as a salt has a different mechanism of action) while the potent and selective MET-inhibitor PF-04217903 was essentially inactive suggesting that GSK3, not MET, inhibition is responsible for tivantinib’s activity in AML cells (Fig. 1c,d).