XIAP and breast neoplasm: Most importantly, downregulation of JNK/c-Jun signaling (by treating cells with JNK inhibitor or c-Jun siRNA) or miR-21 (by treating cells with anti-miR-21 inhibitor) reduces the expression of the target protein, Bcl2, and anti-apoptotic proteins [e.g., IAPs (cIAP1/cIAP2/XIAP)] (Figure 5) in breast tumor cells.