DNMT1 and anaplastic large cell lymphoma: Next, since we observed that doxorubicin treatment induced a clear increase in miR-125b expression in NPM-ALK(+) ALCL cells (Figure 6A), and since its major target is DNA topoisomerase II (Topo II), a DNA-binding protein required for the maintenance of DNA methylation by DNMT1 [22, 23], we assessed the role of Topo II in miR-125b regulation by treating cells with etoposide, a Topo II inhibitor that is part of the CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide and prednisone) chemotherapy regimen, at final concentrations ranging from 100 to 300 nM.