Plerixafor, a CXCR4 antagonist approved to enhance the mobilization and collection of hematopoietic stem cells for autologous transplantation in patients with Non-Hodgkin’s lymphoma and multiple myeloma, is under investigation to be applied for the mobilization of leukemic stem cells, in order to improve their elimination from the bloodstream through chemotherapy. This evidence concerns the gene CXCR4 and non-Hodgkin lymphoma.