FLT3 and acute promyelocytic leukemia: Remarkably, a higher percentage of APL stem-like cells was significantly associated with the S-type PML/RARα transcript (S-type vs. L-type: P < 0.0001; S-type vs. V-type: P = 7.3e-3; Fig. 5a and Supplementary Fig. 15) and FLT3-ITD (P < 0.0001).