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OCTOBER 16-18, 2011 • PORTLAND, OR
P29
CD117 Expression in Adult T-cell Leukemia/
Lymphoma
Margo Santiago, Prashant Tembhare, Constance M.
Yuan, Maryalice Stetler-Stevenson
NCI, NIH, Bethesda, MD, USA
Adult T-cell Leukemia/Lymphoma (ATLL) is a rare
mature T-cell neoplasm believed to be caused by
human T-cell leukemia/lymphotropic virus type-
1. Using fow cytometric immunophenotyping
(FCI), ATLL can be diagnosed and monitored in
patients. The characteristic FCI phenotype is a T
cell population that is CD3 dim, CD4 positive, CD 7
negative, CD25 bright and CD26 negative. An outside
case was referred to the Laboratory of Pathology,
NCI, NIH with reported immunophenotypic studies
demonstrating CD117 positivity in the malignant
T-cells. CD117 is not normally expressed by mature
T-cells. If CD117 positivity is a characteristic
feature of ATLL it could provide a sensitive marker
for diagnosis and monitoring of residual disease.
Therefore a series of seven specimens from patients
with ATLL (6 peripheral blood and 1 bone marrow)
were examined for the expression of CD117 by ATLL
cells. In all seven cases, the malignant ATLL cells and
normal T-cells were CD117 negative. We conclude
CD117 is not a characteristic feature of ATLL and
cannot provide a sensitive test for ATLL disease.
Acknowledgment: This research was supported by the
Intramural Research Program of the NIH, NCI.
POSTER ABSTRACTS