Somatic deletions, point mutations, and oncogenic fusion proteins involving RUNX1 (RUNX1::RUNX1T1, ETV6::RUNX1) and its obligate binding partner CBFβ (CBFβ::SMMHC) are common in Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL), making RUNX1 one of the most frequently mutated genes in leukemia [2, 3]. The gene discussed is CBFB; the disease is leukemia.