PMID- 20118907
OWN - NLM
STAT- MEDLINE
DCOM- 20100615
LR  - 20230210
IS  - 1530-0285 (Electronic)
IS  - 0893-3952 (Print)
IS  - 0893-3952 (Linking)
VI  - 23
IP  - 4
DP  - 2010 Apr
TI  - PAX5-positive T-cell anaplastic large cell lymphomas associated with extra copies 
      of the PAX5 gene locus.
PG  - 593-602
LID - 10.1038/modpathol.2010.4 [doi]
AB  - Cell lineage is the major criterion by which lymphomas are classified. 
      Immunohistochemistry has greatly facilitated lymphoma diagnosis by detecting 
      expression of lineage-associated antigens. However, loss or aberrant expression 
      of these antigens may present diagnostic challenges. Anaplastic large cell 
      lymphoma is a T-cell lymphoma that shows morphologic and phenotypic overlap with 
      classical Hodgkin's lymphoma, which is a tumor of B-cell derivation. Staining for 
      the B-cell transcription factor, paired box 5 (PAX5), has been suggested to be 
      helpful in this differential, as it is positive in most classical Hodgkin's 
      lymphomas, but absent in anaplastic large cell lymphomas. In this study we report 
      four systemic T-cell anaplastic large cell lymphomas that were positive for PAX5 
      by immunohistochemistry, with weak staining intensity similar to that observed in 
      classical Hodgkin's lymphoma. All diagnoses were confirmed by a combination of 
      morphologic, phenotypic, and molecular criteria. Three cases were anaplastic 
      lymphoma kinase (ALK) negative and one was ALK positive. PAX5 
      immunohistochemistry was negative in 198 additional peripheral T-cell lymphomas, 
      including 66 anaplastic large cell lymphomas. Unexpectedly, although PAX5 
      translocations were absent, all evaluable PAX5-positive anaplastic large cell 
      lymphomas showed extra copies of the PAX5 gene locus by fluorescence in situ 
      hybridization (FISH). In contrast, only 4% of PAX5-negative peripheral T-cell 
      lymphomas had extra copies of PAX5. We conclude that aberrant expression of PAX5 
      occurs rarely in T-cell anaplastic large cell lymphomas, and may be associated 
      with extra copies of the PAX5 gene. PAX5-positive lymphomas with morphologic 
      features overlapping different lymphoma types should be evaluated with an 
      extensive immunohistochemical panel and/or molecular studies to avoid diagnostic 
      errors that could lead to inappropriate treatment. As PAX5 overexpression causes 
      T-cell neoplasms in experimental models, PAX5 may have contributed to 
      lymphomagenesis in our cases.
FAU - Feldman, Andrew L
AU  - Feldman AL
AD  - Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 
      55905, USA. feldman.andrew@mayo.edu
FAU - Law, Mark E
AU  - Law ME
FAU - Inwards, David J
AU  - Inwards DJ
FAU - Dogan, Ahmet
AU  - Dogan A
FAU - McClure, Rebecca F
AU  - McClure RF
FAU - Macon, William R
AU  - Macon WR
LA  - eng
GR  - P50 CA097274/CA/NCI NIH HHS/United States
GR  - P50 CA097274-08/CA/NCI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20100129
PL  - United States
TA  - Mod Pathol
JT  - Modern pathology : an official journal of the United States and Canadian Academy 
      of Pathology, Inc
JID - 8806605
RN  - 0 (PAX5 Transcription Factor)
RN  - 0 (PAX5 protein, human)
SB  - IM
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Female
MH  - Gene Dosage
MH  - Humans
MH  - Immunohistochemistry
MH  - In Situ Hybridization, Fluorescence
MH  - Lymphoma, Large-Cell, Anaplastic/*genetics
MH  - Male
MH  - Middle Aged
MH  - PAX5 Transcription Factor/*genetics
MH  - Polymerase Chain Reaction
PMC - PMC2848697
MID - NIHMS167829
COIS- Disclosure/conflict of interest The authors declare no conflict of interest.
EDAT- 2010/02/02 06:00
MHDA- 2010/06/16 06:00
PMCR- 2010/10/01
CRDT- 2010/02/02 06:00
PHST- 2010/02/02 06:00 [entrez]
PHST- 2010/02/02 06:00 [pubmed]
PHST- 2010/06/16 06:00 [medline]
PHST- 2010/10/01 00:00 [pmc-release]
AID - S0893-3952(22)02739-9 [pii]
AID - 10.1038/modpathol.2010.4 [doi]
PST - ppublish
SO  - Mod Pathol. 2010 Apr;23(4):593-602. doi: 10.1038/modpathol.2010.4. Epub 2010 Jan 
      29.