We also established a 3D bone marrow (BM) model using a microgravity bioreactor that recapitulates CLL-BM stromal cell interactions and allows investigation of patient-specific responses to Bruton’s tyrosine kinase (BTK) inhibition with ibrutinib, as well as the dynamic processes of CLL cell mobilization and homing.21 Here, BTK is linked to B-cell chronic lymphocytic leukemia.