The French Stop Imatinib (STIM) study enrolled 100 CML patients who had been in complete molecular response (CMR: consistently negative BCR-ABL PCR using an assay with a sensitivity of 1:105) for a minimum of two years prior to discontinuation of imatinib [18]. Here, ABL1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.