The drug AMD3100 (Plerixafor), a CXCR4 antagonist, was approved as a second-line treatment for patients with multiple myeloma or non-Hodgkin’s lymphoma (De Clercq, 2009); however in a clinical trial as a HIV-1 therapeutic [CXCR4 is one of two co-receptors for HIV-1 (Feng et al., 1996)], AMD3100 was withdrawn from Phase 1 within 30 days due to premature ventricular contractions (Hendrix et al., 2004). This evidence concerns the gene CXCR4 and plasma cell myeloma.