The negative role of BMI1 oncogenic protein can be suggested by the fact that it is co-localized in the cytoplasm of LSC with the BCR-ABL1 P210 protein and with CD26 (8), the dipeptidil peptidase IV (DPPIV) that has been shown to represent a specific marker of CML progenitors (9, 10);. The gene discussed is DPP4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.