NPM1 and acute myeloid leukemia: In multivariable analyses controlling for tumor purity — based on the percentage of BM blasts — and for patient age, the PI24 score was a more powerful predictor of OS than the LSC17 score (52), the IFN-γ–related score (2), and other established AML prognosticators, including FLT3-ITD and NPM1-mutational status at diagnosis (Figure 5B).