GSK137 with an affinity for the BCL6 BTB–POZ domain of 10 nM (pIC50 = 8; Table 1) has a potency of the same order as BI3802 (<3 nM) but produced virtually no detectable reduction in proliferation, only minor derepression of BCL6 target genes and modest G1 cell cycle increases in lymphoma cell lines including DLBCL cell lines. The gene discussed is BCL6; the disease is diffuse large B-cell lymphoma.