T/myeloid MPAL is the second most common MPAL immunophenotype, representing ~20–30% of MPAL cases, and possess a heterogeneous group of gene alterations in transcription factors (WT1, ETV6, and RUNX1), epigenetic/chromatin modifiers (PHF6 and DNMT3A), NOTCH (NOTCH1), signaling pathways (JAK-STAT and RAS), and fusions of ZEB2::BCL11B and NUP214::ABL1 [17,19,28]. The gene discussed is NOTCH1; the disease is mixed phenotype acute leukemia.