JAK2 and diffuse large B-cell lymphoma: To address whether active STAT3 signaling correlated with activity of the JAK2 kinase, which has previously been implicated in STAT3 phosphorylation in DLBCL (Meier et al, 2009), we selected 330 cases of which roughly one half was p‐STAT3‐positive and the other was p‐STAT3‐negative.