Other NF-κB–dependent lymphoma subtypes are not addicted to IκB-ζ signaling. (A) ABC DLBCLs express higher IκB-ζ mRNA levels compared with other NF-κB–dependent and independent lymphoma subtypes. Error bars depict the standard error of the mean. (B) IκB-ζ is highly expressed in the ABC DLBCL cell line HBL-1. In contrast, in cHL, BL, MM, and GCB DLBCL cell lines, only low IκB-ζ expression is detectable by quantitative PCR. Error bars indicate the standard deviation. (C) Knockdown of IκB-ζ by 2 independent shRNAs is not toxic to BL, cHL, and MM cell lines. A positive control shRNA directed against MYC is toxic to all cell lines, whereas a negative control shRNA against MSMO1 is not toxic to any cell line. Representative results from at least 3 independent replicates are shown.