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

12 th Congress of the European Hematology Association
0696
ANALYSIS OF DNA REPAIR GENES VARIANTS IN MULTIPLE MYELOMA PATIENTS
M. Renzulli, 1 C. Terragna, 1 S. Angelini, 2 P. Hrelia, 2 P. Tosi, 1
E. Zamagni, 1 P. Tacchetti, 1 G. Perrone, 1 M. Ceccolini, 1 G. Martinelli, 1
M. Baccarani, 1 M. Cavo 1
1 Inst. of Hemat. Med. Oncol. Seràgnoli, BOLOGNA; 2 Pharmacology Dept., University
of Bologn, BOLOGNA, Italy
Introduction and Aim. A malfunction of the network responsible for
genome stability e.g. DNA repair and high accuracy of DNA synthesis during
DNA replication may be related to the pathogenesis of Multiple
Myeloma (MM), whose tumoral clone is characterized by a remarkable
high genetic instability. Among all the chromosomal alterations so far
described, translocations involving chromosome 14 and several chromosomal
partners are the most frequent and the most importantly correlated
to MM prognosis. In particular, it has been shown that the presence of
t(4;14)(p16;q32) at diagnosis has a unfavourable impact on prognosis. In
this study, a group of 82 MM patients and a group of 259 healthy donors
were genotyped for common SNPs in DNA repair genes. The aim was to
evaluate the overall frequency of these variants in MM patients and in particular
in those patients carrying t(4;14)(p16q32). Methods. PCR-RFLP
assays were used to detect five polymorphisms in the DNA repair genes
APE1, XRCC1, NBS1, XRCC3, and XPD. An RT-PCR assay was adopted
to identify the IgH/MMSET fusion gene, as t(4;14)(p16q32) surrogate.
Results. Allele frequencies in XRCC1, XRCC3, XPD23 and NBS1 SNPs
genes were similar in MM patients and healthy donors. On the contrary,
the APE1 variant genotype was significantly associated to a MM increased
risk (p=0,04). Moreover, genotype combination of polymorphic-XRCC3
and normal-NBS1 had a marginally significant lower frequency in MM
patients, when compared to healthy donors (2,4% vs. 8,5%, p=0,05).
Overall, t(4;14)(p16q32) frequency was 26%. Considering MM patients
with NBS1 variant allele, the incidence of the t(4;14)(p16q32) positive
patients was higher, compared to t(4;14)(p16q32) negative patients (19,1%
vs. 9,8%), however this difference was not statistically significant. Conclusions.
The preliminary results presented here support the hypothesis
that common polymorphisms in DNA repair genes may be an important
modifier of individual susceptibility to MM. In particular, APE1 polymorphisms
may have a role in MM onset. Moreover, the contribution of the
NBS1 variant allele to MM onset or to t(4;14)(p14q32) insurgence cannot
be excluded. Further studies are ongoing in a larger sample-size population.
0697
GENOME-WIDE ANALYSIS OF DNA COPY NUMBER CHANGES IN MULTIPLE MYELOMA
USING HIGH-DENSITY SNP ARRAYS
L . Mosca, 1 L. Agnelli, 1 D. Ronchetti, 2 S. Fabris, 1 K. Todoerti, 1
S. Bicciato, 3 L Baldini, 2 F Morabito, 4 G Lambertenghi-Deliliers, 2
A Neri1 1 Fondazione IRCCS Policlinico, MILAN; 2 Università degli Studi di Milano,
MILAN; 3 Università degli Studi di Padova, PADUA; 4 A.O. Annunziata,
COSENZA, Italy
Background. Multiple myeloma (MM) is characterized by a profound
genomic instability that involves both ploidy and structural rearrangements.
Nearly half of MM tumors are non-hyperdiploid and frequently
show deletion of chromosome 13 and constitutive activation of
CCND1(11q13), CCND3(6q), MAF(16q24), MAFB (20q), or FGFR3/
MMSET (4p16.3) genes as a result of chromosomal translocations involving
the immunoglobulin heavy chain (IGH) locus on chromosome 14q32.
The remaining tumors are hyperdiploid and show a low prevalence of
IGH translocations and chromosome 13 deletions. Despite the remarkable
recent advances, the spectrum of genetic lesions leading to the biological
and clinical variability of MM has not been defined yet. Novel highthroughput
approaches may help to progress into the definition of the profound
genomic instability generating the bio-clinical heterogeneity of plasma
cell dyscrasias. Aims. The purpose of the present study was a genome
wide analysis of genetic lesions in a representative and stratified panel of
MM patients, to provide more insights into the genomic heterogeneity
associated with plasma cell neoplasms. Methods. Genome wide profiling
data have been generated on high-density SNP arrays (50K). After pre-processing,
the piecewise constant estimates of the underlying local DNA
copy number variation was calculated using the DNAcopy Bioconductor
package, which looks for optimal breakpoints using circular binary segmentation
(CBS). The median of the estimated profiles was scaled back
to a nominal multiplicity of two. Inferred copy number of more than 2.3
260 | haematologica/the hematology journal | 2007; 92(s1)
or less than 1.7 corresponded to gain or loss of DNA, respectively. The
regions presenting a copy number of more than 4 were referred to as gains
and subsequently analyzed to investigate copy number alterations. Hierarchical
clustering was performed by using of dChip software. Results.
Hierarchical clustering analysis was used to investigate altered copy number
in 41 MM patients, 7 plasma cell leukaemia (PCL) and 7 normal samples.
By considering only SNPs with copy number alteration in almost
20% of patients, our analysis showed that chromosome 1q gain (p=1×10 –4 )
and chromosome 13 deletion (p=2.3×10 –3 ) are the main genetic aberrations
driving samples grouping. Highly increased copy number DNA levels
were found in six different regions, specifically from chromosome 1q and
19, and those chromosomes involved in hyperdiploidy (7, 9, 11, and 15).
With regard to regions with decreased copy number, we found the
involvement of the two chromosomal regions 18q and 4p not previously
reported that warrant further investigations. Conclusions. Our data reinforce
the importance of using novel high-throughput approaches to provide
insights into the characterization of novel potential genetic lesion in
primary myeloma tumors.
0698
CYTOGENETIC PATTERNS IN MULTIPLE MYELOMA AFTER A PRECEDING MONOCLONAL
GAMMOPATHY OF UNDETERMINED SIGNIFICANCE (MM POST-MGUS) HAVE DIFFERENT
PROGNOSTIC IMPLICATIONS THAN IN MULTIPLE MYELOMA WITH UNKNOWN PRIOR HIS-
TORY
H. Kaufmann, 1 J. Ackermann, 1 V. Odelga, 1 V. Sagaster, 1 T. Noesslinger, 2
M. Pfeilstoecker, 2 A. Keck, 3 H. Ludwig, 3 H. Gisslinger, 1 U. Jaeger, 1
C. Zielinski, 1 J. Drach1 1 Medical University of Vienna, VIENNA; 2 Hanuschspital, Dept. of Medicine III,
VIENNA; 3 Wilhelminenspital, VIENNA, Austria
Background. Patients with monoclonal gammopathy of undetermined
significance (MGUS) may progress to multiple myeloma (MM) or a related
disorder with a probability of 1% per year. However, it is at present
unclear whether or not MM post-MGUS is biologically and clinically different
from MM developing without a durable MGUS-phase (referred to
as MM with unknown prior history, MM-U). Aims. We studied 41 patients
with MM post-MGUS using interphase FISH to determine the cytogenetic
pattern and clinical outcome. Results were compared with cytogenetic
abnormalities found in a reference population of 287 patients with MM-
U. Methods. Interphase FISH analysis of any 14q-translocation,
t(11;14)(q13;q32), t(4;14)(p16.3;q32), 13q-deletions, 17p-deletions. Results.
In MM post-MGUS, a t(11;14) was found to be more frequent than in
MM-U (24% versus 14%) and it was associated with significantly shortened
survival (24 months versus 70 months in MM-U; p=0.01). MM post-
MGUS was further characterized by a higher frequency of 13q-deletions
only (absence of all other specific abnormalities; 28% versus 12% in MM-
U; p=0.02). A 13q-deletion only was an indicator of long survival in MM
post-MGUS (median not yet reached) as opposed to MM-U (median survival,
29 months; p=0.001). 17p-deletions were infrequent in MM post-
MGUS (3% versus 16% in MM-U; p=0.04). Survival times for patients
with t(4;14) and/or 17p-deletions and other abnormalities were similar in
both MM patient cohorts. Conclusions. Our data suggest that t(11;14) and
13q-deletions have distinct prognostic implications in the context of MM
post-MGUS.
0699
REGULATORS OF G1 CYCLIN-DEPENDENT KINASES AND MULTIPLE MYELOMA
M.E. Sarasquete, 1 A. Armellini, 1 R. Garcia Sanz, 1 M.C. Chillon, 1
P. Martin-Jimenez, 1 M. Alcoceba, 1 A. Balanzategui, 1 M. Vargas, 1
M. Fuertes, 2 N.C. Gutierrez, 1 M. Gonzalez, 1 J.F. San Miguel1 1 2 Hospital Universitario de Salamanca, SALAMANCA; Grupo español de Mieloma,
SPAIN, Spain
The current view of the MM pathogenesis presumes that Cyclin D dysregulation
is the early and unifying pathogenic event in this disease. This
would modify the cell cycle activity, which would enhance tumor development.
Cyclins D form complex and activate cyclin dependent kinases
4 and/or 6 (CDK4/6). The active complexes help cells to pass from early
to late G1 phase. CDK4/6 is negatively regulated by the INK4 family of
cell cycle inhibitors by preventing cyclin D binding. Inhibitors from the
Cip/Kip family can also inhibit CDKs. Accordingly, the balance between
D cyclins and CDK inhibitors should play a key role in the behavior of the
tumor cell clone from which MM emerges. Aims. 1.To evaluate the expression
of cyclins D (D1, D2 and D3) and CDK4/6 inhibitors (p15, p16, p18,
p19 and p21) by quantitative PCR in tumor plasma cells 2. To determine