Clinicopathologic features and prognostic impact of isochromosome 17q in chronic myeloid leukemia patients

Background Isochromosome 17q (i17q) is a well-known nonrandom secondary anomaly in chronic myeloid leukemia (CML), which occurs either solely or with other additional anomalies. Objectives The aim of the study was to explore the influence of i17q in CML patients in different phases of the disease and the prognostic impact of acquiring such an anomaly on disease progression, outcome, and response to therapy. Materials and methods Cytogenetic analysis was carried out on 100 CML patients by G-banding and fluorescence in-situ hybridization using LSI BCR/ABL, LSI p53(17p13)/ MPO (17q22) i(17q), CEP 8, and CEP Y probes. Results Isochromosome 17q was detected in 16% of cases. All examined bone marrow smears of i(17q)-positive patients were hypercellular and showed variable degrees of dysplastic changes mainly in myeloid lineage, in the form of hyposegmentation and hypogranulation, together with dysplastic features of megakaryocytes in 70% of them. A highly significant association of i(17q) with poor prognosis was confirmed statistically (P = 0.002) compared with the prognosis in negative patients. The event-free survival of the i(17q)-positive group was 1.6 months compared with 11.5 months in negative patients. However, no statistically significant association was revealed with standard prognostic factors (P 0.05). Conclusion Isochromosome 17q identifies a subgroup of CML with distinct clinicopathologic features and with high risk for aggressive disease progression.