Expression of EDB fibronectin in human lymphomas. Immunohistochemical analyses of cryosections from human lymphoma specimens with the L19 antibody revealed EDB expression in both aggressive and indolent NHLs and in Hodgkin lymphoma. In contrast, no or only very faint staining was observed in non-neoplastic lymph nodes. While the pattern of EDB staining appeared strictly vascular in the majority of the lymphoma cases, a diffuse stromal reaction was observed in some specimens (as exemplified with the CLL sample). DLBCL, diffuse large B cell lymphoma; MCL, mantle cell lymphoma; CLL, chronic lymphocytic leukemia; FL, follicular lymphoma; LN, lymph node. Scale bars, 100 μm.