37
OCTOBER 16-18, 2011 • PORTLAND, OR
P1
WT1 RNA expression in different cell lineages in
normal and leukemic bone marrow
Daphne C. Ang, Fei Yang, Ginny Lanier, Richard
Press, Guang Fan
OHSU, Portland, OR, USA
The WT1 gene is over-expressed in the bone
marrow and peripheral blood of patients with acute
myeloid leukemia (AML) and high expression levels
are prognostic of poor outcomes. WT1 has been
previously shown to be expressed in normal CD34+
bone marrow cells, but at a level about 100 to 1000
times lower than in leukemic cells. However, WT1
expression in other cell lineages including PMN’s,
lymphocytes, and monocytes (in normal and leukemic
samples) is unknown. Bone marrows (BM) from
7 normal, 8 AML, 1 acute promyelocytic leukemia
(APL) and 4 acute lymphoblastic leukemia (ALL)
patients were fuorescence-activated cell sorting
(FACS)-sorted into 4 lineages: CD34+ blasts, CD14+
monocytes (mono), CD45+ lymphocytes (LYMPH),
and neutrophils (PMN) sorted by characteristic
side and forward scatter. FACS-sorted samples
were examined for WT1 expression by quantitative
reverse transcriptase-polymerase chain reaction
and normalized to the ABL reference gene. The
WT1 expression level of normal and ALL patients
were signifcantly lower across all cell lineages as
compared to AML and APL patients (p=.01). Among
AML and APL samples, WT1 was highly expressed,
not only in the blast population but also in the PMN’s
and occasionally in the monocytes. (Figure 1) These
results suggest that WT-1 is aberrantly overexpressed
in myeloid leukemic cells. WT-1 expression is not
solely confned to the blast cells, but is also seen in
the maturing myeloid and monocytic lineages. The
WT-1 expressing leukemic balsts may then ultimately
mature to , neutrophils and monocytes.
POSTER ABSTRACTS