Glioma-associated oncogene homologue 3, a hedgehog transcription factor, is highly expressed in Hodgkin and Reed-Sternberg cells of classical Hodgkin lymphoma

The hedgehog signaling pathway has been shown to play a pathogenic role in diffuse large B-cell lymphoma and anaplastic large cell lymphoma, but has not been assessed in classical Hodgkin lymphoma. Glioma-associated oncogene homologues 1, 2, and 3 are transcriptional effectors of the hedgehog pathway. In this study, we first used real-time quantitative polymerase chain reaction to investigate the expressions of GLI1, GLI2, and GLI3 in 3 classical Hodgkin lymphoma cell lines. GLI1 and GLI2 were variably expressed, but GLI3 was highly expressed in all cell lines. We then used immunohistochemistry to assess glioma-associated oncogene homologues 1, 2, and 3 in 39 classical Hodgkin lymphoma patient samples. Glioma-associated oncogene homologues 1 and 2 were weakly to variably expressed in a subset of classical Hodgkin lymphoma patient samples. In contrast, glioma-associated oncogene homologue 3 showed strong, uniform nuclear expression in virtually all Hodgkin/Reed-Stenberg cells. We then performed an immunohistochemical survey of glioma-associated oncogene homologue 3 expression in 13 cases of nodular lymphocyte predominant Hodgkin lymphoma and 218 non-Hodgkin lymphomas. Most other lymphoma types showed variable or no expression of glioma-associated oncogene homologue 3, with a minor subset of cases of nodular lymphocyte predominant Hodgkin lymphoma, ALK-positive and ALK-negative anaplastic large cell lymphoma, and B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma showing a glioma-associated oncogene homologue 3 staining pattern indistinguishable from classical Hodgkin lymphoma. Our data provide a rationale to further investigate the biologic significance of glioma-associated oncogene homologue 3 in classical Hodgkin lymphoma biology.