EZH2 and lymphoma: Next, in order to establish the subtype of lymphoma, we performed immunohistochemistry for PAX5, a transcription factor indicative of lymphoblastic cells, which showed robust nuclear labeling, and MUM1/IRF4, another transcription factor that identifies nongerminal center B-cells and that has been linked with poor survival and indicates a lack of EZH2, an enzyme that suppresses the pro-plasmacytic program, and further indicates loss of function of the germinal center phenotype.