Clinical implications of der(9q) deletions detected through dual-fusion fluorescence in situ hybridization in patients with chronic myeloid leukemia

Poor outcomes of some chronic myeloid leukemia ((CML) patients have been associated with submicroscopic der(9q) deletions, particularly the 5′ ABL region. Deletion profiles of 120 BCR/ABL+ CML patients were studied using the dual-fusion fluorescence in situ hybridization probe. Poor prognosis was associated with 5′ABL deletion but not with 3′BCR deletion. Overall survival (OS) and chronic phase duration (CPD) were significantly shorter for 5′ABL deletion than for those without deletions (OS time: 27 vs. 61 months, P = 0.02; CPD: 17 vs. 56 months, P = 0.02). In addition, when isolated 5′ABL deletion patients were compared to those without it, a greater impact on prognosis was detected (OS time: 18 vs. 59 months, P = 0.0008; CPD: 7 vs. 54 months, P = 0.0003). Isolated 5′ABL deletion seems to have a greater impact on survival than does concomitant 5′ABL and 3′BCR deletion, although the difference was not statistically significant in this aspect (OS time: 18 vs. 28 months, P = 0.08).