RARB and acute promyelocytic leukemia: The 2017 “WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues” introduced the APL with RAR variant subtype, encompassing genes from all 3 RAR family members (RARA, RARB, RARG), capable of mimicking the morphology, immunophenotype, and clinical presentation of APLs other than those with PML::RARA positivity.