Furthermore, we reveal that when PDX-ALL cells are co-cultured with 3D BM-MSC-spheroids they show greater reduction in sensitivity, compared to the 2D co-culture arm, against dexamethasone, ABT-199 (a molecularly targeted therapy against BCL-2 positive blood cancers), and dexamethasone-ABT-199 combination in a sample subgroup that exhibited reducedin vivo efficacy (obtained from previously unpublishedin vivo data existing in the lab from earlier studies). This evidence concerns the gene BCL2 and hematopoietic and lymphoid system neoplasm.