To simulate the effect of the lymph node microenvironment [52] on fadraciclib actions, we supplemented the CLL cells with B-cell activation (BCA) medium consisting of anti-CD40 monoclonal antibody, IL-4, and anti-IgM to mimic the T-cell stimulation and engagement of B-cell receptor signaling. Here, IL4 is linked to B-cell chronic lymphocytic leukemia.