PTH pretreatment inhibits myeloma progression.

SCID-rab mice were pretreated with PTH for 4 weeks and then injected with BN stroma-dependent myeloma cells (six mice/group) or with myeloma cells from one of three patients (for each patient's cells, a total of six hosts were used: three pretreated with saline, three pretreated with PTH). Treatment with PTH continued throughout the experimental period (see schema of the experimental design in Figure 4A). (A) In vivo live-animal imaging revealed similar luciferase (Luc) activity in BN myeloma cells a few hours after injection into saline- and PTH-pretreated hosts, indicating that similar numbers of myeloma cells were injected into the implanted bones in both groups. (B) Pretreatment with PTH inhibited growth of BN myeloma cells in SCID-rab mice. (C–E) Pretreatment with PTH delayed growth of primary myeloma cells from three different patients.