MYC and plasma cell myeloma: The sensitivity to JKY-2-169 growth inhibition of U266 multiple myeloma (MM) cell line (IC50 of 46 μM), which expresses L-Myc instead of c-Myc and it was the least susceptible among MM cell lines to 10058-F4 growth inhibition (IC50 ~100 μM), as well as the sensitivity of HO15.19 Myc-null cells comparable to that of TGR1 cells, with IC50s of 20 and 14 μM, respectively, implied that JKY-2-169 had additional off-target effects and/or nonspecific toxicities.