[1469] Detection of IGK and IGH Gene Rearrangements in Non-Hodgkin Lymphomas by BIOMED-2 PCR Primers

Alia Nazarullah, Monique Maldonado, Yao Wang, Kumari Vadlamudi, Marsha Kinney, Wieslaw Furmaga, Hongxin Fan. University of Texas Health Science Center at San Antonio, San Antonio, TX

Background: BIOMED-2 immunoglobulin heavy chain (IGH) gene rearrangement (GR) assays are widely used in the diagnosis of lymphoproliferative disorders, and include reactions for complete VH-JH and incomplete DH-JH GR. IGK GR is a useful clonality marker, especially in germinal center/ post germinal center B-cell lymphomas characterized by higher rates of somatic hypermutation. We evaluated the BIOMED-2 IGH and IGK assays in fresh/frozen and formalin-fixed paraffin-embedded (FFPE) tissue of patients with non-Hodgkin lymphomas (NHL).
Design: 77 NHL cases from 2007 - 2012 were analyzed [20 fresh/frozen (5 blood, 13 bone marrow, and 2 other), and 57 FFPE (26 skin, 13 lymph node and 18 other) samples]. DNA was extracted by EZ1 DNA Tissue Kit (Qiagen) for FFPE and PUREGENE® DNA Purification Kit (Gentra Systems) for fresh/frozen samples. GR detection was performed by IGH and IGK Gene Clonality Assay Kit (InVivoScribe Technologies), and capillary gel electrophoresis (ABI 3130xl Genetic Analyzer). VH-JH and IGK assays were performed in 77 cases and DH-JH assay in 46 cases.
Results: Using BIOMED-2 IGH and IGK primers, duplicate clonal GR were detected in 87% (67/77) NHLs, with 90% (18/20) using fresh/frozen, and 86% (49/57) using FFPE samples (See table 1).

Table 1
 IGHIGHIGKIGH + IGK
 VH-JHDH-JHVH-JH + DH-JH  
MZL35/42 (83%)12/24 (50%)37/42 (88%)21/42 (50%)38/42 (90%)
Cutaneous MZL19/23 (83%)10/14 (71%)21/23 (91%)11/23 (48%)22/23 (96%)
Nodal MZL5/5 (100%)1/4 (25%)5/5 (100%)4/5 (80%)5/5 (100%)
Extranodal MZL11/14 (79%)1/6 (17%)11/14 (79%)6/14 (43%)11/14 (79%)
FL6/10 (60%)0/5 (0%)6/10 (60%)5/10 (50%)6/10 (60%)
CLL/SLL8/9 (89%)6/8 (75%)8/9 (89%)6/9 (67%)9/9 (100%)
DLBCL10/11 (91%)3/6 (50%)10/11 (91%)6/11 (55%)11/11 (100%)
Others3/5 (60%)2/3 (67%)3/5 (60%)3/5 (60%)3/5 (60%)
Total66/81 (82%)27/50 (54%)68/81 (84%)44/81 (54%)71/81 (88%)
MZL - Marginal zone lymphoma, FL - Follicular lymphoma, CLL/SLL - Chronic lymphocytic leukemia/small lymphocytic lymphoma, DLBCL - Diffuse large B-cell lymphoma

DH-JH assay detected 2 VH-JH negative cases (2 cutaneous MZLs) and IGK assay detected 4 VH-JH negative cases (2 cutaneous MZLs, 1 CLL/SLL, and 1 DLBCL). Among the 26 skin FFPE samples, clonal VH-JH were detected in 85% (22/26), DH-JH in 67% (10/15), and IGK in 54% (14/26) samples.
Conclusions: IGH VH-JH assay is one of the most sensitive markers for clonality in NHLs. DH-JH and IGK GR are useful surrogate markers for clonality detection in difficult cases; their combined use along with VH-JH GR increases clonality detection rate in cutaneous MZL by 13% and in NHL by 6%.
Category: Hematopathology

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 224, Monday Morning

 

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