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Blood, 15 December 2008, Vol. 112, No. 13, pp. 5190-5192. Prepublished online as a Blood First Edition Paper on September 22, 2008; DOI 10.1182/blood-2008-04-148791.
NEOPLASIA BCR-ABL fusion transcript types and levels and their interaction with secondary genetic changes in determining the phenotype of Philadelphia chromosome–positive leukemiasDepartments of 1 Hematopathology, 2 Leukemia, and 3 Stem Cell Transplantation and Cellular Therapy, University of Texas M. D. Anderson Cancer Center, Houston It remains unresolved how different BCR-ABL transcripts differentially drive lymphoid and myeloid proliferation in Philadelphia chromosome–positive (Ph+) leukemias. We compared BCR-ABL transcript type and level with kinase domain (KD) mutation status, genotype, and phenotype in 1855 Ph+ leukemias. Compared with e1a2/p190 BCR-ABL cases, de novo e13-e14a2/p210 Ph+ lymphoid leukemia more frequently showed CML-type background, had higher blast-normalized BCR-ABL transcript levels, and more frequent persistent BCR-ABL transcript in the absence of detectable lymphoblasts. Secondary lymphoid blast transformation of CML was exclusively due to e13/e14a2/p210 BCR-ABL but was associated, at a much higher level than p210 myeloid transformation, with acquisition of new KD mutations and/or Ph genomic amplification. In contrast, myeloid blast transformation was more frequently accompanied by new acquisition of acute myeloid leukemia-type chromosomal aberrations, particularly involving the EVI1 and RUNX1 loci. Therefore, higher kinase activity by mutation, transcriptional up-regulation or gene amplification appears required for lymphoid transformation by p210 BCR-ABL.
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| Copyright © 2008 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||