Clinical And Experimental Studies Of Derivative Chromosome 9 Deletion In Patients With Ph-positive Leukemia

【Research background】Chronic myeloid leukemia (CML) is a clonal hematologic malignancy that arise in the stem cell compartment .Its cytogenetic hallmark is a reciprocal t(9;22) chromosomal translocation known as the Philadelphia chromosome and this translocation results in the formation of chimeric fusion gene BCR/ABL which is thought to play a central role in the pathogenesis of CML. Nearly 30% of adult acute lymphoblastic leukemia(ALL) patients also had t(9;22) translocation and BCR/ABL fusion gene. Recently fluorescence in site hybridization (FISH) techniques has allowed identification of large deletion adjacent to translocation breakpoint on the derivative 9 chromosome [der(9)] in about 10%～15% of Ph+CML and small part of Ph+ALL .Several studies have demonstrated that CML patients who carry derivative chromosome 9 deletions exhibit a shorter chronic phases ,a more rapid progression to blast crisis and a shorter survival. To investigate the status of der(9)deletion and the association between the deletion and clinical prognosis in Ph+CML and Ph+ALL patients in our country ,the BCR/ABL dual color, dual fusion DNA probes was used to perform the interphase FISH in 105 Ph+CML and 31 Ph+ALL patients.【Objective】To determine the frequency of the deletion of derivative 9 [der(9)] in Ph-positive chronic myeloid leukemia (CML) patients and Ph+ALL patients ,and to assess the association between this deletion and the type of Ph translocation or clinical prognosis.