Subgroup of patients with Philadelphia-positive chronic myelogenous leukemia characterized by a deletion of 9q proximal to ABL gene:: expression profiling, resistance to interferon therapy, and poor prognosis

A major deletion of the region proximal to the rearranged ABL gene on 9q was found in 14/94 (15%) of chronic myelogenous leukemia Philadelphia-positive patients by interphase fluorescent in situ hybridization with the BCR/ABL extra signal dual-color probe. Preliminary results indicated that the prognosis of the deletion 9q patients is probably worst than that of the non-deletion 9q patients. Twelve of the 14 deletion 9q patients were treated with alpha -interferon and none had a major cytogenetic response. The median duration of the chronic phase in patients not undergoing BMT was significantly shorter fur the deletion 9q patients as compared to the non-deletion 9q patients (p = .0144). DNA microarray technology was performed in order to compare the gene expression patterns between the two groups of patients. A number of genes exhibiting differential expression. especially involving cell adhesion and migration, were identified. This finding may identify a sub-group of CML patients with different cell properties and a relatively poor prognosis. (C) 2001 Elsevier Science Inc. All rights reserved.