pp242 is effective against primary MM samples. (A) Isolated primary MM cells from 3 bone marrow aspirates were exposed to increased concentrations of pp242 for 24, 48, or 72 hours. Number of viable cells was then recorded. Data presented as percent of control (no inhibitor) where the control counts at 24, 48, or 72 hours were arbitrarily made 100%. At top of some bars is the percentage viability determined by trypan blue staining. For each primary specimen at several time points, percent apoptosis was also determined and the data represent percent apoptosis above control (no inhibitor). The latter control groups showed a mean percent apoptosis at 48 hours incubation of 28% and mean percent apoptosis at 72 hours of 39%. (B) One of the patient's cells were treated with increasing concentrations of pp242 for 2 hours after which immunoblot was performed for the designated proteins.