KCL22-r/GFP-luciferase cells are derived from human lymphoblast-like cell line KCL22-r by stably integration of a constitutive GFP and Firefly luciferase stably expression construct. KCL22-r cells are a variant of the KCL22 cell line that is specifically used to study resistance to imatinib, a tyrosine kinase inhibitor commonly used to treat chronic myeloid leukemia (CML). Imatinib targets the BCR-ABL fusion protein, which is a key driver of CML.  KCL22-r/GFP-luciferase cells stably express GFP and Firefly luciferase, can be used for in vitro assays and in vivo imaging.