Clonal dynamics in a murine model of MM. (A) Serum protein electrophoresis performed at the indicated weeks on a biclonal Vk*MYC mouse shows the emergency at 80 weeks of a secondary clone that becomes dominant by 100 weeks. Arrows highlight the M-spike secreted by the dominant clone. Arrowhead points to the M-spike secreted by the competed out clone. (B) BM cells from a donor mouse (D) with a triclonal myeloma were transplanted into 3 wt congenic mice recipient mice (R). Serum protein electrophoresis shows engraftment of only 1 of the 3 clones in all 3 recipient mice. Arrows highlight the M-spike secreted by the dominant clone. Arrowheads point to the M-spikes secreted by the competed out clones. (C-E) BM cells from Vk*MYC myeloma-bearing mice (Donor) were transplanted into either wt congenic mice (wt) or recipient Vk*MYC mice with preexisting MM (R). Serum protein electrophoresis was performed at the indicated weeks after transplantation. Arrows highlight the M-spikes secreted by the donor mouse MM cells and arrowheads points to the preexisting M-spikes in the recipient mice.