To adequately compare in vivo responses between previously tested ABT-737 and current ABT-199 treatment of human derived NB cell lines xenografted into mice, we employed the same Mcl-1 dependent (IMR5) and Bcl-2 dependent (NB-1643) cell lines used in prior published assays, using an identical treatment design as previously described ([19] and Methods). Here, MCL1 is linked to neuroblastoma.