Rituximab combined with doxorubicin decreased NF-κB activity. Rituximab combined with doxorubicin significantly decreased the phosphorylated and the activated forms of NF-κB (P65) in Namawa cells, without variation of total NF-κB (A). Addition of NF-κB inhibitor PDTC increased the antiproliferative effect of doxorubicin on Namawa cells (B) and induced PRDM1β down-regulation (C).