The cells in ETV6-RUNX1 pB-ALL are generally regarded as malignant counterparts of normal B-cell precursors, but ETV6-RUNX1 pB-ALL origin is still the subject of continuing discussion, given the fact that human disease is diagnosed at late stages and cannot be monitored during its natural evolution from its cell of origin [6–8]. The gene discussed is RUNX1; the disease is acute lymphoblastic leukemia.