PRDM1 was expressed in lymphoma cells of non-GCB DLBCL and related to IRF4 expression. With different protein expression patterns revealed by immunohistochemisty (A-B), PRDM1 transcripts were expressed in microdissected lymphoma cells of DLBCL non-GCB subtype (A) but not of GCB subtype (B) (40×/0.75 NA non-oil objective). PRDM1 expression was related to IRF4 expression (C). IRF4-positive lymphoma cells coexpressed IRF4, PRDM1α, and PRDM1β (D) (10×/0.75 NA non-oil objective; small figure: 150×/0.75 NA non-oil objective).