Binding of arsenic to these proteins, such as PML-RARα (an oncogenic protein in acute promyelocytic leukemia)24 and poly(ADP-ribose) polymerase-1 (PARP-1, a nuclear protein enzymes involved in DNA damage response)25, 26, could alter their conformations and functions as well as their interactions with other functional proteins. This evidence concerns the gene PARP1 and acute promyelocytic leukemia.