STAT5A and diffuse large B-cell lymphoma: STAT3Sβ increases its transcriptional activity by interacting with c-Jun.17 STAT3 can dimerize with STAT5a/b32 and STAT1.33 In ABC DLBCL, the IFN-STAT1 pathway is lethal and thus basal STAT1 activity is low.34 Unphosphorylated STAT3 can bind to p65 of NF-κB.35 All of these proteins are expressed in ABC DLBCL.7, 13, 36 We cannot rule out the possibility of these interactions in DLBCL cells, but dimerization with non-STAT3 proteins seems unlikely to be functionally important, given little or no rescue by any of the single variants of STAT3.