MTOR and myeloproliferative neoplasm: As shown in Figure 3, colony formation from MPN patients was dose-dependently reduced by mTOR inhibitors; the data reported in Table 2 indicate that MPN progenitor growth could be inhibited with IC50 drug concentration significantly lower than control cells (in case of RAD001, from 4.7 to 13-fold lower and in case of PP242 from 2.6 to 6.1-fold lower, depending on colony type), pointing to a substantial degree of drug selectivity against MPN cells.