Haematologica 2003 - Supplements

In conclusion, we identified a novel recurrent primary
translocation involving 14q32, i.e. t(14;20)(q32;q12). Aberrant
expression of MafB and/or TIMAP may be involved in the
oncogenic transformation of myeloma cells, harboring this
t(14;20).
028
Studies on Cyclin D1 Gene Amplification and the t(11;
14) Chromosome Translocation in Multiple Myeloma
T. Guglielmelli, G. Mattioli, E. Giugliano, P. Scaravaglio, G.
Rege-Cambrin, G. Saglio
Dipartimento Scienze Cliniche e Biologiche, Orbassano, Italy
Malignant diseases are characterized by abnormal regulation of
the cell cycle and by uncontrolled cell division.
CYCLIN D1 is a protein derived from the CCND1 gene and it is
responsible for the transition from G1 (resting) phase of the cell
cycle to the S phase (Dna synthesis) via phosphorylating the
product of the retinoblastoma gene (pRB). CYCLIN D1 is
overexpressed in 50% of human mammary carcinoma; in
parathyroid adenoma and mantle cell lymphoma CYCLIN D1 is
activated by translocation. In many cancers, including colon,
breast, lung, head and neck, CYCLIN D1 is activated by gene
amplification.
In Multiple Myeloma (MM), the role of CYCLIN D1 is less
established. Approximately 30% of MM express CYCLIN D1
when detected by immunohistochemical techniques, and around
50% of untreated MM patients are characterized by a CYCLIN
D1 overexpression when studied by RT-PRC. Only one previous
study analyzes amplification of CCND1 gene by FISH and
detected the amplification in 38% of cases.
The aim of this study is to evaluate overexpression of CCND1
gene in MM at diagnosis. Furthermore we investigate if CCND1
overexpression derives from the t(11;14) translocation or it is
activated by gene amplification.
Plasma cell were purified from bone marrow samples with
CD138 magnetic beads.
Two sets of probes were used for interphase FISH investigations:
LSI CCND1/CEP11 (Vysis, UK) dual color probe for the
detection of CCND1 amplification and LSI IGH/CCND1 (Vysis,
UK) dual color probe for the detection of the t(11;14))
translocation. FISH analysis was applied to a series of 25
patients at diagnosis.
Results. Cyclin D1 amplification was found in 9 out of 25
samples analyzed (36%).
Trisomy 11 occurred in 7 patients (28%). 4 patients were positive
for the t(11;14) (16%). The cut-off level for CYCLIN D1
amplification was defined at 20%.
Combined analysis shows CYCLIN D1 overexperession in 3 of
the 4 cases bearing the t(11;14), in 2 of the 7 cases with trisomy
11 and in 5 cases without the t(11;14) (55% of the amplified
cases, 16% of all cases).
Of note, the amplification of CCND1 gene was not detected in a
sample despite the finding of the t(11:14). In this case breakpoint
on chromosome 11 may occur at least 400 Kb upstream the
CCND1 gene.
Conclusion. A CCND1 overexpression is frequently observed in
MM patients (36%). Amplification of CCND1 gene was not
correlated with the t(11;14) translocation in 5 out 9 patients
(55%). In a subset of MM alternative mechanism of CCND1
amplification occurs. The same mechanism has been observed in
the majority of solid tumors. This subgroup of myeloma may
have a different biological and clinical behavior.
029
The t(9;14)(p13;q32)/IGH-PAX5 rearrangement is not a
hallmark of low grade lymphoplasmacytic lymphoma
Wlodarska I, Michaux L, Poppe B, Moreau E, Herens C,
Bastard C, De Paepe P, Yigit N, De Paepe A, Dastugue N,
Hagemeijer A, Speleman F
The t(9;14)(p13;q32) is a rare chromosomal translocation
presumably associated with low grade lymphomas showing
plasmacytoid differentiation. On a molecular level this aberration
results in a deregulated expression of the PAX5 gene (9p13) due
to the proximity of IGH transcriptional enhancers/promoters.
PAX5 encodes the BSAP (B-cell specific activator protein)
transcription factor that normally is downregulated at the
transition between the mature B-cell and plasma cell. Thus, the
plasmacytoid phenotype of t(9;14)-associated lymphomas
possibly reflects an inappropriate expression of PAX5 that should
be turned off at terminal differentiation to plasma cells.
The t(9;14)/IGH-PAX5 rearrangement detected in approximately
50% of lymphoplasmacytic lymphoma (LPL) by Iida et al (1996)
has been occasionally reported in other lymphoma subtypes
including FL, MZL and DLBCL (with or without a preceding
phase of a low-grade lymphoma). These latter observations
suggest that the t(9;14) either reflects the underlying low grade
malignancy, or that its association with LPL is not specific. In
order to clearly define the diagnostic and prognostic significance
of a t(9;14) we performed a retrospective multi-center study of
patients with a suspected or proven t(9;14)(p13;q32).
Interestingly, in 3 of these cases this translocation was hidden by
three-way rearrangements detected by MFISH analysis. In order
to facilitate the screening for IGH-PAX5, we designed two and
three color interphase FISH assays with probes spanning the IGH
and PAX5 loci and validated their application in the KIS-1 cellline
carrying the t(9;14)(p13;q32). Using that approach, a
coinciding rearrangement of the PAX5 and IGH loci was
demonstrated in all patients. It is worth to note that two
additionally analyzed DLBCL cases with a postulated variant
t(3;9)(q27;p13) (Iida et al, 1996) showed the 9p13 breakpoint
outside PAX5 (400kb proximal to the gene) pointing other
recurrent 9p13 targets in NHL. Particularly interesting is that only
2 of 8 cases with the identified t(9;14) were diagnosed as low
grade NHL (Waldenström's macroglobulinemia and MZL), and
only one of them showed features of plasmacytoid differentiation.
All the remaining patients (6/8) suffered from de novo DLBCL.
Predominant occurrence of this high grade lymphoma in the
present series of IGH-PAX5 positive tumors indicates that
translocation t(9;14)(p13;q32) has a much wider clinical
spectrum as previously assumed, and therefore may not be
regarded as a genetic hallmark of low grade lymphomas with
features of plasmacytic differentiation.
2.2 Chromosome instability
030
Centrosomal disregulation in myeloma: Role of the
receptor for hyaluronan mediated motility (RHAMM)
Chris A Maxwell , Tony Reiman, M.D. , Gordon, Chan,
Ph.D., Jonathan Keats, Andrew Belch, M.D. , and Linda M
Pilarski, Ph.D.
Oncology, Cross Cancer Institute, Edmonton, AB, Canada, T6G
1P4.
Multiple myeloma (MM) is characterized by infiltration of
monoclonal plasma cells in the bone marrow, chromosomal
instability (CIN) and translocations involving the
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