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

have an early manifestation of typical myeloma, the majority show only
slow progression for up to 6 years. The detected FISH abnormalities in
these stable patients are not significantly different from those in the more
aggressive cases suggesting that other as yet unidentified factors play a
significant role in the phenotype of t(4;14) disease. These results confirm
that treatment decisions for this group of patients should be based on clinical
behaviour rather than the presence of a poor prognosis genetic abnormality.
0887
DELETIONS OF CHROMOSOMES 6Q AND 13Q,AND TRISOMY 4 ARE THE MOST COMMON
CYTOGENETIC ABNORMALITIES IN WALDENSTROM MACROGLOBULINEMIA. PRELIMINARY
RESULTS OF A MULTICENTRIC STUDY
F. Nguyen-Khac, 1 E. Chapiro, 1 C. Barin, 2 N. Gachard, 2 A. Daudignon, 2
C. Terre, 2 V. Eclache, 2 I. Luquet, 2 V. Soenen, 3 C. Henry, 2 H. Mossafa, 4
S. Ramond, 5 B. Perissel, 2 C. Bastard, 2 S. Struski, 2 C. Bilhou-nabera, 2
M.-J. Gregoire, 2 E. Callet-Bauchu, 2 M.-J. Mozziconacci, 2 F. Mugneret, 2
H. Merle-beral, 1 V. Leblond1 1 Hopital Pitie-Salpetriere, PARIS; 2 Cytogenetique, TOURS; 3 Hematologie, LILLE;
4 Cerba-pasteur, CERGY-PONTOISE; 5 Cytogenetique hotel-dieu, PARIS, France
The genetic bases of Waldenström Macroglobulinemia (WM) are poorly
understood. We studied by conventional cytogenetic (CC) and Fluorescence
in situ hybridization (FISH) analysis a cohort of 83 untreated
WM patients, enrolled in a prospective randomized trial from the French
Cooperative Group on Chronic Lymphocytic Leukemia and Waldenström
Macroglobulinemia ( FCG-CLL/WM). The sex ratio was 57M/26F,
the mean age at diagnosis was 67 years [40-85]. The mean percentage of
lymphoplasmacytic cells was 50% [8-90]. CC was systematically performed
on bone marrow or peripheral blood, and FISH analysis carried
out using 7 probes CEP4, CEP12, 13q14, 11q22 ( ATM), 17p13 (TP53),
IGH Abbott, 6q21 Q-Biogene, on metaphases and interphase nuclei. Out
of 67/83 successful karyotypes, 45% showed abnormalities. There were
7 (11%) 6q deletions, 5 (8%) trisomy 4/partial trisomy 4, 3 (5%) trisomy
18, 2 (3%) trisomy 12. Using FISH deletions of 6q21 were observed in
14/50 cases (28%), 13q14 in 8/54 cases (15%), TP53 5/54 cases (9%),
ATM 3/53 cases (6%). Trisomy 4 was present in 7/53 cases (13%), and
trisomy 12 in 3/55 cases (5%). No rearrangement of IGH was observed
in the first 17 analyzed cases. The 6q deletion is the most frequent reported
cytogenetic abnormality in WM. We found 28% of 6q deletion, a low
percentage compared to the literature [39-54%]. This could be explained
either by the difference in the probe used or we did not select for lymphoplasmacytic
cells before cytogenetic analyses. Interestingly we confirmed
our recent observation that trisomy 4 was frequent in WM (15%
if partial trisomy 4 was included). Furthermore we observed in this large
series a frequent 13q14 deletion (15%). In conclusion, cytogenetic abnormalities
in WM differ from those commonly reported in other B-cell neoplasms
and confirm the originality of this disease. 6q deletion is frequent
compared to CLL or marginal zone lymphoma (MZL) and 13q14 deletion
is rare compared to CLL. In our series trisomy 12 is rare compared to atypical-CLL
and MZL. We didn’t observed cytogenetic involvement of the
IGH locus, which is frequent in multiple myeloma or lymphoplasmocytic
lymphoma. Finally trisomy 4 is present in WM but not reported in other
B-cell malignancies. Searches for correlations with clinical and other
biological parameters are ongoing.
12 th Congress of the European Hematology Association
Genomics and proteomics
0888
PHOSPHOPROTEOMIC PROFILING OF PEDIATRIC B-ALL PATIENTS USING REVERSE PHASE
PROTEIN ARRAYS
B. Accordi, 1 V. Espina, 2 G. Te Kronnie, 1 L. Liotta, 2 E. Petricoin III, 2
G. Basso1 1 2 University of Padua, PADOVA, Italy; George Mason University, MANASSAS,
VA, USA
Background. The outcome for children with Acute Lymphoblastic
Leukemia (ALL) is improved in the last few decades with current therapies,
but 30% of patients still resist to conventional therapies. Leukemia
patients with similar molecular aberrations react differently to drug treatment,
proving that there must be altered signalling pathways other than
those already targeted in therapy. Although some genetic defects had
been associated to different therapeutic responses, for many malignancies
the signal transduction pathways (STPs) involved in the neoplastic
process are not yet identified. Aims. Our study aims to provide such information
in pediatric B-ALL patients using phosphoproteomic measurement
of STPs in order to identify patient subgroups characterized by
aberrantly activated phosphoproteins. The identification of differently
altered STPs could offer possibilities for targeted therapy and a means of
patient stratification. Methods. Reverse Phase Protein Arrays (RPPA),
which can quantitatively measure hundreds of phosphorylated proteins,
were employed to profile the working state of cellular STPs in 120 pediatric
B-ALL specimens collected prior to treatment at the Pediatric Oncohematology
Laboratory (University of Padova, Italy). Bone marrow white
blood cells lysates were immobilized in dilution curves on nitrocellulose
coated slides, and antibody staining (1 slide =1 antibody) was revealed
using DAB. Images of antibody-stained arrays were analyzed using the
Microvigene Software. The data processing generates a single value for
each sample relative to each phosphorylated protein. Molecular network
analysis and phosphoprotein profiling were performed using commercially
available software. The phosphorylation status of 92 key signalling
proteins was analyzed. Clinical data, such as immunophenotype,
response to therapy and chromosomal translocations, were collected for
all the patients. Different patients subgroups were compared in order to
find differentially activated phosphoproteins to better map the biology
of the disease and to identify new drug targets relative to the deranged
pathways. Results. In a first study, prednisone good responder (PGR)
patients were compared with prednisone poor responder (PPR) patients.
Profiling of phosphoproteins shows that an aberrantly activated pathway
in PPR patients results in the hyperactivation of the transcription factor
NFkappaB, a known target of steroid therapy. NFkappaB hyperactivation
could explain why these patients are not able to respond to prednisone,
thus aberrantly activated proteins upstream to NFkappaB could
represent new targets for kinase inhibitors. In the same patient cohort,
non-translocated patients were compared to MLL rearranged patients.
Analysis of MLL rearranged patients samples reveal an activated pathway
that leads to the hyperactivation of Bcl-2. This activation could provide
a survival advantage to the blast cells, blocking the normally functioning
apoptotic pathway. Conclusions. Proteins in the deranged NFkappaB and
Bcl-2 signalling pathways observed within these B-ALL patients may represent
new targets for targeted kinase inhibitors already used in other
contexts or yet to be developed. The discovery of the molecular mechanisms
related to drug resistance could play an important role for individualizing
therapy and may reveal new strategies to improve therapy stratification
and treatment outcome.
0889
MIRNA EXPRESSION PROFILING IN ADULT ACUTE MYELOID LEUKEMIA IDENTIFIES
DISTINCT SUBCLASSES
L. Bullinger, 1 S. Sander, 1 K. Holzmann, 1 A. Russ, 1 H. Kestler, 1
J.R. Pollack, 2 R.F. Schlenk, 1 K. Dohner, 1 H. Dohner1 1 University of Ulm, ULM, Germany; 2 Stanford University, STANFORD, USA
Background. Acute myeloid leukemia (AML) encompasses a large number
of morphologically similar but at the molecular level quite distinct
variants. Recurrent cytogenetic aberrations have been shown to constitute
markers of diagnostic and prognostic value. However, despite recent
successes in detecting novel molecular markers like FLT3, CEBPA, and
NPM1 mutations, and despite recent advances in gene expression profiling
treatment stratification is still difficult and the biology underlying dis-
haematologica/the hematology journal | 2007; 92(s1) | 331