Extra

Summary

Normal expression and function

Diagnostic role

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SUMMARY TABLES

Note The colour and % refer to the proportion of cases expressing the marker. Additional comments on strength, or site of expression (if relevant) are given below the table. For full details of key click here. For further information about a particular disease state click <I> adjacent to the condition name

Expression in primitive cell types
AML	CMML	B ALL	Burkitt	T ALL	ETP ALL <I>	MPAL <I>	Hgns <I>
5-20%*	<5%	80-100%**	80-100%	<5%	<5%	40-80%	80-100%

Notes: **While a good marker of B lineage it may not be expressed in more primitive phenotype ALL, there is also a recognised abberrant expression in AML (particularly cases with t)8;21)

Expression in mature B cell neoplasms
CLL	MCL	FL	MZL	HCL	DLBCL	LPL	PCL
80-100%*	80-100%	80-100%	80-100%**	80-100%**	40-80%	80-100%	5-20%***

Notes: Level of expression is important: *low expression in CLL; **typically high expression in HCL; ***generally absent in PCs

Expression in mature T cell neoplasms*
ATLL	CTCL/Sezary	T-PLL	T-LGL	NK-LGL
<5%	<5%	<5%	<5%	<5%

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summary tables

1. expression by acute leukaemias and by haematogones file freq pro-b all hi early pre-b all hi pre-b all hi early b all rare pro-t all rare mature-t all rare aml * hi haemato-gones

2. expression by b-lymphoproliferative disorders hi cll * hi pll** hi mcl hi fl hi hcl** hi hclv hi mzl poss lpl rare pcs

• typically weak ** typically strong

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The principle use of CD103 is the identification of HCL and its distinction from related diorders. CD103 also identifies a subset of T lymphocytes.

normal expression and function CD103 belongs to the integrin family of adhesion proteins and acts as an adhesion receptor that directs a subset of T cells to home to the intestinal endothelium and other mucosal sites (binding to E-cadherin). In normal tissues CD103 has a very restricted pattern of expression, found mainly on normal intraepithelial T cells of either alpha-beta or gamma-delta type. It is however also expressed by some peripheral regulatory T cells (TRegs) and on specialised dendritic cells in the gut mucosa and mesenteric lymph nodes.

diagnostic role

In flow cytometry CD103 emerged as a useful marker following the unexpected discovery that it was consistently expressed on hairy cell leukemia with relatively high specificity. although in common with most markers in the disorder CD103 is not fully specific, so must be considered in conjunction with other markers. CD103 is not generally found on other lymphomas including splenic marginal zone lymphoma .

other useful information

In histopathology CD103 is used to identify enteropathy-associated T cell lymphoma, and in lung CD103 has been used in bronchoalveolar lavage to diagnose pulmonary sarcoidosis.

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summary tables

1. expression by acute leukaemias and by haematogones

file rare pro-b all rare early pre-b all rare pre-b all rare early b all rare pro-t all rare mature-t all rare aml rare haemato-gones

• expression is reported to be associated with bcr-abl1 expression

2. expression by b-lymphoproliferative disorders file rare cll rare pll rare mcl rare fl hi hcl hi hclv rare mzl rare lpl rare pcs

link flow cytometry key considered a strong indicator to distinguish hcl and hclv from mzl