RARA and acute promyelocytic leukemia: Two therapeutic agents in clinical use for APL, all-transretinoic acid (ATRA), and arsenic trioxide (As2O3) can target PML-RARα and induce PML-RARα degradation through ubiquitin-proteasome pathway, resulting in a complete remission with the differentiation and apoptosis of leukemic cells [54–56].