IGH-BCL2⁺DLBCLs manifest high levels of endogenous SOX9. (A) immunohistochemical staining of SOX9 protein in tissue samples from a DLBCL cohort (n = 114). Original magnification ×200. Bar represents 100 μm. SOX9 immunostainings are denoted as (+), (++), and (+++) to indicate the expression levels of SOX9. Negative staining is denoted as (−). Normal tonsil tissue was used as the control. SOX9 highlighted scattered follicular dendritic cells and showed only background staining in the germinal centers. Results of immunoblot (B) and qRT-PCR (C) analysis of endogenous SOX9 protein or SOX9 mRNA levels in DLBCL cell lines. (B-C) Data represent the mean ± standard deviation (SD) from technical triplicates.