Background: Classic Hodgkin lymphoma (CHL) and nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) are clinically distinct entities, with different prognostic and treatment implications. In addition, several large B-cell lymphomas and some T-cell lymphomas can mimic CHL. Differentiating these entities from CHL is crucial for ensuring appropriate therapy. GATA3 is a T-cell transcription factor involved in T-cell maturation and has been previously shown to be overexpressed in CHL cells via gene expression profiling. We investigated the utility of GATA3 immunostain in differentiating CHL from NLPHL and other mimicking entities.
Materials and methods: We accrued 17 NLPHLs, 49 CHLs [23 nodular sclerosis (NS), 3 syncytial variants, 3 lymphocyte rich and 13 mixed cellularity types], 4 primary mediastinal large B-cell lymphomas (PMBLs), 2 Epstein-Barr virus (EBV) positive diffuse large B-cell lymphomas (DLBCLs) (EBV+LBCLs), 2 T-cell/histiocyte-rich large B-cell lymphomas (TCHRBCLs), 1 gray zone lymphoma, and 2 tissue microarrays consisting of 72 DLBCLs. One slide from each was stained with GATA3 and percent positive tumor cells and intensity of nuclear expression was semiquantitatively graded independently by 2 board certified hematopathologists.
Results: GATA3 was positive in 80% of CHLs. Both percent positivity and intensity of staining varied greatly. Syncytial variant of NS subtype showed the highest positivity rate (3/3; 100%), followed by NS (20/23; 87%), mixed cellularity (9/13; 70%), and lymphocyte rich (2/3; 67%). GATA3 was negative in all NLPHLs, EBV+LBCLs, TCRBCLs, and DLBCLs stained. The single gray zone lymphoma and 3/4 PMBLs were positive.
Conclusions: Nuclear expression of GATA3 can be used to delineate CHL from NLPHL. GATA3 positivity effectively excludes NLPHL with 100% negative predictive value. However, as 20% of CHL can be negative for GATA3, CHL cannot be ruled out with negative GATA3. Additional findings include GATA3 positivity among PMBLs, whereas all 72 DLBCLs were negative for GATA3. This finding further highlights similarities between CHL and PMBL.