CYP24A1 and B-cell chronic lymphocytic leukemia: Examples of preclinical development of CLL-directed small-molecule therapies include the novel tubulin-targeting agent pyrrolo-1,5-benzoxazepine-15 (PBOX-15), which induces apoptosis in poor prognostic subgroups of CLL patients [30], while 25-hydroxyvitamin d-24-hydroxylase (CYP24A1) inhibitors have demonstrated efficacy in primary chronic CLL cells [31].