Immunohistochemical analysis of NF-κB components in DLBCL cell lines and primary DLBCL samples. (A) Representative GCB-like (MS) and ABC-like (LP) DLBCL cell lines were used for immunohistochemical staining for pp65 and p52. (B) Representative immunohistochemical analysis of DLBCL tissue arrays of 43 primary DLBCL biopsies with high/low p52, and high/low pp65. Tissue arrays with duplicate samples were scored using an automated analysis system for percentage of positive cell staining for p-IκBα and for the presence of the NF-κB components, pp65 and p52 (supplemental Figure 1). (C) Prevalence of cases that are positive (> 30% staining) for pIκBα, pp65, and p52 in the DLBCL subgroups GCB, ABC, and non-profiled (NP). (D) Analysis of pp65 expression (average of pp65-positive cells) in the DLBCL subgroups GCB, ABC, and non-profiled (NP).