Consistent with increased engraftment of BCR-ABL1T315I+ proviral clones and more aggressive disease of BCR-ABL1T315I+ CML [20, 23], the disease clonality was significantly higher in recipients of BCR-ABL1T315I+ than BCR-ABL1+ BM (P = 0.035, Fig. 1e, f). Here, BCR is linked to chronic myelogenous leukemia, BCR-ABL1 positive.