DHFR and leukemia: In addition, the molecular docking analysis suggests that cytotoxic activity of IA and IB against all leukemia cell lines used in this study may be associated with the effects on the five targets used: human topoisomerase IIα, human topoisomerase IIβ, human dihydrofolate reductase, human methylenetetrahydrofolate dehydrogenase, and human B-cell lymphoma 2 protein.