Haematologica 2003 - Supplements

can be considered as two entities, one with exposure to ongoing
mutation with a very long history and the other lacking this
intraclonal variation destined for the early progression and
development of clinical symptoms. Definition of subtypes of
myeloma using arrays need to incorporate these different types of
plasma cell from which myeloma may putatively arise.
References
Davies FE, Morgan GJ. Innovative techniques
Davies FE, Rawstron AC, Owen RG, Morgan GJ. Controversies
surrounding the clonogenic origin of multiple myeloma. Br J
Haematol 2000, 240-241.
Fenton JAL, Pratt G, Rawstron AC, Sibley K, Rothwell D, Yates
Z, Dring A, Richards SJ, Ashcroft AJ, Davies FE, Owen RG,
Child JA, Morgan GJ. Genomic characterization of the
chromosomal breakpoints of t(4;14) of multiple myeloma
suggests more than one possible aetiological mechanism.
Oncogene 2003, 1-11.
Proffitt J, Fenton J, Pratt G, Yates Z, Morgan G . Isolation and
characterisation of recombination events involving
immunoglobulin heavy chain switch regions in multiple myeloma
using long distance vectorette PCR (LDV-PCR). Leukemia
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Roddam PL, Rollinson S, O'Driscoll M, Jeggo PA, Jack A,
Morgan GJ (2002). Genetic variants of NHEJ DNA ligase IV can
affect the risk of developing multiple myeloma, a tumour
characterised by aberrant class switch recombination. J Med
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Sibley K, Fenton JA, Dring AM, Ashcroft AJ, Rawstron AC,
Morgan GJ. A molecular analysis of the t(4;14) in multiple
myeloma. Br J Haematol 2002, 514-520.
Zojer N, Ludwig H, Fiegl M, Stevenson FK, Sahota SS. Patterns
of somatic mutations in VH genes reveal pathways of Clonal
transformation from MGUS to multiple myeloma. Blood 2003.
2. Genetic heterogeneity in MM: impact
on diagnosis and therapy
P2.1
ELEVATED EXPRESSION OF WNT SIGNALING
ANTAGONISTS DKK1 AND FRZB BY MALIGNANT
PLASMA CELLS IS STRONGLY ASSOCIATED WITH
LYTIC BONE DISEASE IN MYELOMA
Erming Tian 1,2,* , Fenghuang Zhan 1,2,* , Ronald Walker 3 ,
Kelly McCastlain 1,2 Joth Jacobson 4 , Erik Rasmussen 4 , John
Crowley 4 , Joshua Epstein 2 , Bart Barlogie 2 , and John
Shaughnessy Jr 1,2, .*These authors contributed equally to
this work
1
Donna and Donald Lambert Laboratory of Myeloma Genetics, 2
Myeloma Institute for Research and Therapy, 3 Department of
Radiology, University of Arkansas for Medical Sciences, Little
Rock, AR, 72205 and 4 Cancer Research and Biostatistics, 1730
Minor Ave. STE 1900, Seattle, WA 98101-1468.
Focal lytic bone lesions and systemic osteopenia are major causes
of morbidity and mortality in multiple myeloma (MM). Bone
destruction is linked to increased osteoclast activity, which can be
traced to perturbations in IL-6, MIP1 and RANK signaling 1 .
Bisphosphonates have been shown to be highly effective agents
in reducing the progression of bone lesions, however, a lack of
repair to preexisting damage suggests that a defect in osteoblast
function is also an important component of the bone destruction
process. Indeed, studies have shown that whereas osteoblast
numbers are increased in MM, their functional capacity is
dramatically impaired 2 .
Bone lesions are located adjacent to medullary plasmacytoma
suggesting that MM PC secrete factors that activate osteoclast
and/or induce osteoblast apoptosis. Thus, in an effort to identify
genes linked to bone disease we performed a genome wide scan
for altered gene expression patterns in a comparison of CD138-
enriched PC from newly diagnosed MM with no radiological
evidence of osteolytic bone lesions (n = 87) or ≥ 3 lytic lesions (n
= 83). Of a total of ~12,000 genes studied, 367 were identified as
being significantly differentially expressed (P < .001) using a
combination of 2, Wilcoxin Rank, and SAM statistical analysis.
Of these, 229 were higher and 138 lower in PC from MM with
lytic lesions. Elevated expression of genes associated with cell
proliferation, e.g. PCNA, TYMS, PRKDC, CENPA and TOP2A
was seen in MM with lytic lesions. In contrast ARHE, IL-6R,
WNT10B, and the B-cell receptor molecules SLAM, TACI, and
LNHR, were the most significantly under expressed genes in MM
with lytic lesions. Importantly, the WNT signaling antagonists,
FRZB 3 and DKK1 4 , represented the only genes coding for
secreted factors within the top 50 up-regulated genes. Moderately
high expression (Signal >1000) of DKK1 and/or FRZB was seen
in 74% of all MM cases with 46% of all cases expressing both
genes above 1000. Importantly, neither gene was detectable by
microarray in PC from 45 normal bone marrow donors or 10
Waldenstrom’s macroglobulinemia, a PC malignancy that lacks
bone disease. Although FRZB was expressed at similar levels in
MGUS and MM, DKK1 was rarely found in PC from this
condition. Immunohistochemistry of bone biopsies revealed an
inter- and intra-patient variability in expression in MM PC, yet a
strong correlation with DKK1 and FRZB gene expression data. In
patients with high gene expression, protein expression was
heterogeneous and tended to be highest in PC lining the bone.
Interestingly, in cases with low FRZB gene expression intense
FRZB staining was observed in microvessels. Simultaneous
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