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Chapter 11 Haematological malignancy: aetiology and genetics / 163
10 5 10 5
10 4 10 4
cCD3 PE-A 10 3 CD34 PerCP-Cy5-5-A 10 3
10 2 10 2
10 2 10 3 10 4 10 5 10 2 10 3 10 4 10 5
nTdT FITC-A CD2 APC-A
10 5 10 5
10 4 10 4
CD33 PE-A 10 3 CD4 APC-A 10 3
10 2 10 2
10 2 10 3 10 4 10 5 10 2 10 3 10 4 10 5
CD7 FITC-A CD3 PerCP-Cy5-5-A
Figure 11.14 FACS analysis of acute lymphoblastic leukaemia, T lineage. The blast cells express cCD3, TdT,
CD34, CD7 and CD2. (Courtesy of Immunophenotyping Laboratory, Royal Free Hospital, London.)
by the tumour cells distinguishes them from a Value of g enetic m arkers in
normal polyclonal population which express both κ m anagement of h aematological
and λ chains, usually in a κ : λ ratio of 2 : 1 (see m alignancy
Fig. 18.4 ).
The detection of genetic abnormalities may be
important in several aspects of the management of
Immunohistology
patients with leukaemia or lymphoma.
Antibodies can also be used to stain tissue sections
with fluorescent markers and this is known as
immunohistology or immunohistochemistry . Th e Initial d iagnosis
presence and architecture of tumour cells can
be identified by visualization of stained tissue Many genetic abnormalities are so specific for a
sections under the microscope (Fig. 11.15 ). Th e particular disease that their presence determines
clonal nature of B - cell malignancies can be shown that diagnosis. An example is the t(11; 14) translo-
in tissue sections by staining for κ or λ chains. A cation which defines mantle cell lymphoma. Clonal
malignant clonal population (e.g. in B - cell NHL) immunoglobulin or TCR gene rearrangements are
will express one or other light chain but not both useful in establishing clonality and determining the
(see Fig. 20.5 ). lineage of a lymphoid malignancy.
