BCL6 and B-cell chronic lymphocytic leukemia: Our co-immunoprecipitation studies, performed in MEC1 CLL cells, show no direct interaction between BACH2 and BCL6, but the majority of the interaction partners found in the shared protein interaction network suggested cooperation between them in key signalling processes, such as the ubiquitin-mediated protein degradation pathway, nucleic acid metabolism, and cellular homeostasis (Table S7).