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

12 th Congress of the European Hematology Association
0132
ANALYSIS OF AML/MDS CELL LINES HIGHLIGHTS GENES TARGETED BY CONCOMITANT
5Q DELETION AND 11Q23 AMPLIFICATION
B. Schneider, S. Nagel, M. Kaufmann, H.G. Drexler, R.A.F. MacLeod
DSMZ, BRUNSWICK, Germany
Background. In addition to chromosome rearrangements causing a variety
of gene fusions, MLL1 may be targeted by regional chromosomal
copy-numberr gains amplifying the 11q23 region (amp-11q23) in acute
myeloid leukaemia (AML) and myelodysplastic syndromes (MDS).
However, conflicting reports suggest that other genes at 11q23 may be
targeted. Amp-11q23 is invariably partnered by deletions affecting the
long-arm region of chromosome 5 (5q-) implying collaboration of genes
at these loci. Aims.To identify genes targeted by 5q-/amp-11q23 and
characterize AML/MDS cell line models for this disease entity. Methods.
Fluorescence in situ hybridization with tilepath clones covering 11q2
and 5q; genomic (G) and reverse transcription (RT) q(uantitative)-PCR.
Results. Key candidate target genes, notably, DDX6, FLI1 and MLL1, displayed
mean 4.5x genomic amplification by G-qPCR. Of these, only
MLL1 displayed consistently elevated gene expression by RT-qPCR,
averaging 5.6x upregulation overall. We then analyzed the expression of
known downstream targets of MLL1-gene fusion rearrangements in an
AML context, including, MEIS1, HOXA7, HOXA9, CDKN1B, CDKN2C
- where only the last named displayed consistent upregulation. All amp-
11q23 cell lines displayed 5q- with a common deleted region at 5q31
extending from 133-140 Mbp. Of 5q genes recently identified as possible
deletion targets, only BRD8 and KCT2 were consistently downregulated,
with expression levels at ~0.25x, and ~0.4x, control levels, respectively.
In addition, although genomic copy number increases at 8q24
were present, MYC was not consistently upregulated. Summary and Conclusions.Taken
together, these results highlight MLL1 as a salient target
of 11q23 amplification and implicate CDKN2C as a possible downstream
target. Furthermore, our data imply that leukemogenic overexpression
requires downregulation of BRD8 (a nuclear receptor coactivator)
and KCT2 (a membrane receptor protein) in AML/MDS cells. These
findings highlight candidate loci to serve as potential therapeutic targets
in AML/MDS, together with cell lines which may be useful in further
investigations.
Figure 1. MLL1 amplification.
0133
ANALYSIS OF 1Q21 COPY NUMBER CHANGES IN PATIENTS IN PROGRESSION AND
RELAPSE OF MULTIPLE MYELOMA
J. Balcarkova, V. Scudla, M. Holzerová, H. Pospisilova, M. Zemanova,
J. Bacovsky, K. Indrak, M. Jarosova, M. Jarosova
University Hospital Olomouc, OLOMOUC, Czech Republic
Chromosomal abnormalities have biologic and prognostic significance
in multiple myeloma (MM), especially among patients with relapsed
and refractory disease. The primary translocations occur as early and
perhaps as initiating events during the pathogenesis of MM. However,
these translocations are not sufficient for the malignant progression of
this disease and the accumulation of additional genetic alterations are
necessary for a fully malignant phenotype. Previous comparative genomic
hybridization (CGH) studies have revealed, that the gain or amplification
of 1q, consistently involving 1q21, is associated with a poor prog-
48 | haematologica/the hematology journal | 2007; 92(s1)
nosis of MM. The aim of this study was to determine the 1q21 copy
number changes in patients with a relapse and progression of the disease
using molecular cytogenetic methods and to correlate these findings
with other cytogenetic changes and clinical parameters. We analyzed
bone marrow cells from 23 MM patients, 13 with a relapse of
MM and 10 with a progression of MM. All patients (median of the age
60 years) were examined by conventional cytogenetics and by FICTION
method with locus specific probes 1q21/1p36 (QBiogene, MP Biomedicals,
CA), RB1, IgH, IgH/CCND1, IgH/FGFR3 and centromeric probes
for chromosomes 7, 9, 11, 15, 17 (Abbott-Vysis, Downers Grove, IL,
USA). Comparative genomic hybridization (CGH) (Abbott-Vysis,
Downers Grove, IL, USA) and multicolor fluorescence in situ hybridization
(M-FISH) (MetaSystem, Altussheim, Germany) were used to detect
chromosomal changes in 2 patients with a complex karyotype. Using
FICTION method we detected copy number changes of 1q21 in 12
(52%) out of 23 analyzed cases. All patients with copy number changes
of 1q21 had other cytogenetic abnormalities: deletion of RB1 gene and
t(4;14) were found in 4 (17%) patients, deletion of RB1 gene and deletion
of IgH gene in 4(17%), trisomy of examined chromosomes in 2
(9%), a single t(11;14) in 1(4%) and a single t(4;14) in 1(4%) patient.
The detected cytogenetic changes and clinical data were analyzed and
will be presented.
This work is supported by grant NR-8183-4 and MSM 6198959205
0134
FREQUENCY AND CLINICAL IMPLICATIONS OF ADDITIONAL CHROMOSOMAL
ABERRATIONS IN ETV6/RUNX1 POSITIVE CHILDHOOD ALL
Z. Zemanova, 1 K. Michalova, 1 L Babicka, 1 M. Jarosova, 2 M Holzerova, 2
A. Oltova, 2 M. Hruba, 2 K. Muzikova, 3 J Zuna, 3 J Trka, 3 V. Mihal, 2
J. Sterba, 2 R. Formankova, 4 P. Sedlacek, 5 A. Vrzalova, 4 J. Stary5 1 General Faculty Hospital, PRAGUE 2, 2 Faculty Hospital, OLOMOUC, ;
3 CLIP - Childhood Leukaemia Investigation, PRAGUE; 4 Faculty Hospital
Motol, PRAGUE; 5 2nd Medical Faculty of Charles Univ., PRAGUE, Czech
Republic
Background. Cryptic translocation t(12;21)(p13;q22) which give origin
to the hybrid gene ETV6/RUNX1 is one of the most reliable predictors
of a favourable clinical outcome in childhood ALL. Despite of generally
favourable prognosis of ETV6/RUNX1 positive ALL, late relapses may
occur within this group of patients with current therapy. One of the
reasons could be the high instability of the genome of leukemic cells,
which is manifested at the chromosomal level by formation of secondary
abnormalities. Additional chromosomal abberations were proved
in about 50-70% of patients with ETV6/RUNX1 positive ALL. Genetic
changes that are most frequently associated with t(12;21) are the deletion
of the wild type ETV6 allele, trisomy of chromosome 21 and/or
duplication of the ETV6/RUNX1 fusion gene. Also non-specific structural
and/or complex chromosomal rearrangements could be found. Aims.
The aim of the present study was to evaluate the frequency and clinical
implications of additioanal and/or complex chromosomal aberrations for
prognosis of chidren with ETV6/RUNX1 positive ALL. Methods. For the
assessment of ETV6/RUNX1 fusion gene RT-PCR and/or double target
interphase FISH (I-FISH) with locus-specific probe (Abbott-Vysisä) were
used. Karyotypes were analyzed by conventional G-banding and by
molecular cytogenetic methods. Structural and/or complex chromosomal
aberration were proved by FISH with whole chromosome painting
probes (Cambioä) and/or by mFISH with the 24XCyte probe kit (Meta-
Systemsä). Results. We examined 126 children with ALL and
ETV6/RUNX1 fusion gene detected by RT-PCR and/or I-FISH. Patients
were diagnosed between 1995 and 2006, age ranged between 15 months
and 16.6 years (median 4.2 years). Relapse appeared in 20 children
(15.9%), five patients died. In 75 children (59.5%) we found besides
t(12;21)(p13;q22) additional chromosomal aberrations, the most frequently
trisomy or tetrasomy of chromosome 21 (23 cases), deletion of
non-translocated ETV6 allele (29 cases), deletion of 6q (8 cases) and/or
rearrangements of the long arm of chromosome X (6 cases). Complex
karyotypes were identified in 40 children (31.7%). In twelve of them
variant translocations of chromosomes 12 and 21 with other partners
were observed. Univariate analysis indicated that patients with complex
aberrations in ETV6/RUNX1 positive cells had significantly shorter
event-free survival (p=0.01). Conclusions. In this cohort of children with
ETV6/RUNX1 positive ALL complex karyotypes were connected with
worse prognosis. Our findings suggest the importance of comprehensive
molecular cytogenetic analysis in identifying additional and/or complex
chromosomal aberrations in ETV6/RUNX1 positive cells.
Supported by grants MSM 0021620813, VZ064165 and MSM LC535 .