Meanwhile, studies suggested that cryptic formation was not only limited to PLZF::RARα, but also identified in APL with PML::RARα (41, 42), IRF2BP2::RARα (43), TBL1XR1::RARα (44), and FIP1L1::RARα (45). This evidence concerns the gene IRF2BP2 and acute promyelocytic leukemia.