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Expression of programmed cell death 1 ligand 2 (PD-L2) is a distinguishing feature of primary mediastinal (thymic) large B-cell lymphoma and associated with PDCD1LG2 copy gain.
- Source :
-
The American journal of surgical pathology [Am J Surg Pathol] 2014 Dec; Vol. 38 (12), pp. 1715-23. - Publication Year :
- 2014
-
Abstract
- Primary mediastinal (thymic) large B-cell lymphoma (PMBL) and diffuse large B-cell lymphoma (DLBCL) are tumors with distinct clinical and molecular characteristics that are difficult to distinguish by histopathologic and phenotypic analyses alone. Programmed cell death 1 ligand 2 (PD-L2) is a cell surface protein expressed by activated macrophages and dendritic cells that binds PD-1 on T cells to inhibit immune responses. Amplification and/or translocations involving chromosome 9p24.1, a region that includes PDCD1LG2-encoding PD-L2, is a common event in PMBL but not DLBCL and suggests that PD-L2 expression might be a distinguishing feature of PMBL. We developed an assay for the immunohistochemical detection of PD-L2 protein in fixed biopsy specimens (PD-L2 IHC), which we applied to a cohort of PMBLs and DLBCLs. For a subset of cases, we correlated the results of PD-L2 IHC with PDCD1LG2 copy number (CN) as determined by quantitative polymerase chain reaction. Twenty-three of 32 (72%) PMBLs but only 1 of 37 (3%) DLBCLs were positive by PD-L2 IHC. Among PMBLs with PDCD1LG2 CN gain, all were positive by PD-L2 IHC. One PMBL without CN gain was positive by PD-L2 IHC. When expressed in PMBL, PD-L2 was restricted to tumor cells and not detected on intratumoral macrophages. We conclude that PD-L2 protein is robustly expressed by the majority of PMBLs but only rare DLBCLs and often associated with PDCD1LG2 copy gain. PD-L2 IHC may serve as a useful ancillary test for distinguishing PMBL from DLBCL and for the rational selection of patients for therapeutic antibodies that inhibit PD-1 signaling.
- Subjects :
- Diagnosis, Differential
Gene Amplification
Gene Dosage
Humans
Immunohistochemistry
Polymerase Chain Reaction
Programmed Cell Death 1 Ligand 2 Protein genetics
Biomarkers, Tumor analysis
Lymphoma, B-Cell diagnosis
Lymphoma, Large B-Cell, Diffuse diagnosis
Mediastinal Neoplasms diagnosis
Programmed Cell Death 1 Ligand 2 Protein biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 1532-0979
- Volume :
- 38
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- The American journal of surgical pathology
- Publication Type :
- Academic Journal
- Accession number :
- 25025450
- Full Text :
- https://doi.org/10.1097/PAS.0000000000000297