IL6 and B-cell chronic lymphocytic leukemia: Thus, we next explored whether exposure to CD40 ligand (CD40L), B-cell activating factor (BAFF), tumor necrosis factor (TNF)-α, interleukin (IL)-6 or IL-4, which are microenvironment-derived cytokines reported to enhance CLL viability and drug resistance (37), could subvert the activity of EC-7072.