Deletion of BCR region 3 ' in chronic myelogenous leukemia

The t(9;22)(q34;q11) produces the BCR/ABL fusion gene which codifies a 210 kb protein with a strong tyrosine kinase activity and is involved in cellul ar development and growth. Because this translocation is a reciprocal event , it could give rise to a second fusion gene, ABL-BCR, on the derivative 9q +. We analyzed the influence of the 3' M-BCR deletion on the clinical pictu re at diagnosis and disease outcome in 57 patients with a clinical diagnosi s of CML. Molecular studies were done on DNA from peripheral blood leukocyt es or bone marrow with the restrictions enzymes Bg[Il, EcoR1, HindIII, and BamHI, and the BCR 3' probe (transprobe 1) (Oncogene Science Inc.), which e ncompasses almost all of the 5.8 Kb of the M-BCR t,ene area. In 18 patients Southern blot analysis showed deletion of the 3' end of BCR gene (32.7%). There were no significant differences between patients with or without dele tion, either in the clinical and laboratory data at the disease diagnosis o r at the disease outcome. The absence of differences between the patients w ith and without 3' BCR deletion supports the hypothesis that the hybrid gen e ABL-BCR does not have an important role in leukemogenesis in CML cases. ( C) 2001 Elsevier Science Inc. All rights reserved.