RARA and acute promyelocytic leukemia: As(III) binding to ZnF proteins may also stimulate their degradation, as shown for the histone acetyltransferase TIP60 in human HEK293T cells treated with 2–5 μM As(III) [133] and the oncogenic PML-RARα fusion protein in APL cells at the therapeutic concentration of 1 μM [37].