Cyclin D1 expression and polysomy in LP cells of nodular lymphocyte predominant Hodgkin lymphoma

• Published in: Annals of diagnostic pathology 2016
• Main Authors: Cho, Benjamin B, Kelting, Sarah M, Gru, Alejandro A, LeGallo, Robin D, Pramoonjago, Patcharin, Goldin, Teresa A, Heitz, Christopher T, Aguilera, Nadine S
• Format: Article
• Language: English
• Subjects: Pathology
• ISSN: 1092-9134
• DOI: 10.1016/j.anndiagpath.2016.10.003

Abstract Cyclin D1 protein expression in lymphocytes is classically associated with mantle cell lymphoma. While increasingly recognized in other lymphoproliferative disorders, cyclin D1 expression and CCND1 gene abnormalities have not been well-studied in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). Using a double stain for CD20/cyclin D1, we quantified cyclin D1 expression in 10 cases of NLPHL and correlated those findings with SOX11 expression, CCND1 gene abnormalities and clinical data. For comparison, we examined five cases of T cell/histiocyte-rich large B-cell lymphoma (THRLBCL). All cases of NLPHL stained for cyclin D1 showed at least rare positivity in LP cells. In four cases, at least 20% of LP cells were positive for CD20/cyclin D1. Neither SOX11 expression nor CCND1 gene rearrangement was found in any of the cases, but fluorescence in situ hybridization showed a proportion of the large cells with three to four copies of non-fused IGH and CCND1 signals or three intact CCND1 break-apart signals. Further study with CCND1/CEP11 showed polysomy in 6 of 9 cases with cyclin D1 expression and 5 of 16 NLPHL not examined for cyclin D1. Two of five cases of THRLBCL, showed rare positive staining for CD20/cyclin D1; one case showed polysomy with CCND1/CEP11. Results show that cyclin D1 may be expressed in LP cells without SOX11 expression or CCND1 translocation. Polysomy with increased copies of CCND1 may account for cyclin D1 expression in some cases. Cyclin D1 expression is not useful for distinguishing NLPHL from THRLBCL and has no apparent clinical significance in NLPHL.