MPO and acute myeloid leukemia: Reporting this finding seems of utmost importance to avoid misdiagnosis of ALL cases immunoreacting with MPO as AML or MPAL (Arber et al., 2001, Li et al., 2019), where isoMPO expression in IHC can be a confounder or a diagnostic challenger for lineage assignment in AL (Li et al., 2019; Du et al., 2020).