While FOXM1 protein expression levels were low in both BM-derived B-cell precursors and mature B cells, patient-derived pre-B ALL samples revealed 2- to 60-fold higher FOXM1 protein levels compared with B cells or B-cell precursor populations (P=0.0014 and P=0.0215, respectively; Student’s t-test; Fig. 2b,c). Here, FOXM1 is linked to acute lymphoblastic leukemia.