Clones from the human promyelocytic leukemia cell line NB4 were generated in our laboratory by limiting dilution (CL1, CL2, CL3, and CL4) and then individually exposed to increasing concentrations of ATO, thus obtaining corresponding ATO-resistant clones (CL1-R, CL2-R, CL3-R and CL4-R), as previously reported [7]. This evidence concerns the gene ADGRL3 and acute promyelocytic leukemia.