IHC analysis of SOX11. (a) IHC analysis using SOX11-C1 antibody showed bright nuclear staining in 100% of MCL (TMA) cases. Most other tissues including, B and T lymphoblastic lymphomas, FL, CLL, HCL, tonsil sections and non-malignant bone marrow show no evidence of nuclear SOX11 staining, except Burkitt’s lymphoma where two of four cases showed moderate nuclear staining. Representative stainings of MCL and control tissues are shown. (b) SOX11-C1 antibody enabled reclassification of previously positive HCL cases that lack SOX11 mRNA expression. Representative staining of SOX11 polyclonal antibody and SOX11 C1 antibody is shown.