MCL1 and neuroblastoma: The finding that Mcl-1 depletion does not impair neuroblastoma cell viability is in accordance with previous results demonstrating that Mcl-1 depletion sensitizes neuroblastoma cells to paclitaxel, but does not exert significant effects on neuroblastoma cell viability on its own.33 Hence, the anti-neuroblastoma effects of YM155 do not appear to be caused by Mcl-1 depletion.