Detection of pSTAT3/STAT3 expression on untreated DLBCL tumors. (A) By immunohistochemistry (IHC). (B) Representative pSTAT3 staining in paraffin-embedded tissues from DLBCL tumors (original magnification ×400). (C-D) Western blotting was performed to assess pSTAT3 and tSTAT3 expression in DLBCL patients (n = 7; C); CD19⁺ normal B cells (n = 2); and DHL2 (DLBCL cell line; D).