12th Congress of the European Hematology ... - Haematologica

0174
RELATION BETWEEN LOW PML-RARα LEVELS, FLT3-ITD, OVEREXPRESSION OF CXCR4
GENE AND UNFAVORABLE PROGNOSIS IN ACUTE PROMYELOCYTIC LEUKEMIA
M.C. Chillón, 1 C. Fernández, 1 C. Santamaría, 1 R. García-Sanz, 1
A. Balanzategui, 1 P. Martín-Jiménez, 1 A. Armellini, 1 M. Alcoceba, 1 M.E.
Sarasquete, 1 M. Vargas, 1 F. Ramos, 1 L. Guerras, 2 M. González, 1
J.F. Jesús Fernando 1
1 Hospital Universitario de Salamanca, SALAMANCA; 2 Hospital Clínico de
Valladolid, VALLADOLID, Spain
Background. The quantification of PML-RARα fusion transcripts have
become an important part of the routine clinical practice. Moreover,
there is an increasing interest in gene expression analyses for identifying
different subclasses of AML. However, few clinical studies have been
carried out in this way, and there are discrepancies concerning their prognostic
significance. Aims. 1) To determine the correlation of PML-RARα
levels, FLT3 mutations and gene expression patterns with pre-treatment
characteristics of 141 newly diagnosed APL patients. 2) To evaluate the
prognostic significance of these alterations to identify subsets of patients
at increased risk of relapse. Methods. Real-time quantitative RQ-PCR
(TaqMan technology) was used. The normalized copy number (NCN)
of fusion gene was reported as: number of PML-RARα copies per 1×10 4
ABL copies. Genes encoding multi drug resistance proteins (MDR1 and
MRP1), the chemokine receptor CXCR4, the tyrosine kinase receptor
FLT3 and growth factors upregulated in APL (HGF and FGF13) were
studied. Results. 84 (59.6%), 5 (3.5%) and 52 (36.9%) patients showed
the bcr1, bcr2 and bcr3 PML-RARα isoforms, respectively. The median
NCN was 4100 with a wide range of expression (1100-35000). The low
levels of transcripts (NCN