While short (less than 30 minutes) treatment with doxycycline had no inhibitory effect on NF-κB activation in OCI-Ly10 cells (data not shown), an ABC-DLBCL cell line that displays constitutive NF-κB signaling [11, 13], incubation of these cells with doxycycline for 12 hours decreased mRNA levels of several NF-κB targets (Figure 1A), which had been shown previously to be regulated by NF-κ B in these cells (cyclin D2, EBI3 and IκBα) [13, 14], or exhibited the greatest response to doxycycline treatment among the queried NF-κB targets in the cMAP database (MCL-1). Here, EBI3 is linked to diffuse large B-cell lymphoma.