A fraction of Nras^Q61R/+; Vκ*MYC mice develop MM. (A) Acronyms of transgenic mouse lines and illustration of IgG1-Cre induction scheme. (B) SPEP was performed on representative mice from each group serially bled at the indicated weeks. The brackets show the γ-globulin component of the serum. (C) Kaplan-Meier survival curves (left) and disease incidences (right) of different groups of animals. MM is defined as CD138⁺B220⁻ cells being >10% in BM, spleen, and/or LN along with end-organ abnormalities. (D) Flow cytometric analysis of B220 and CD138 expression on cells from BM, spleen (SP), and LN. Representative density plots from each group are shown. (E) Representative images of hematoxylin-and-eosin (H&E)-stained BM, SP, liver, LN, and kidney sections; scale bar, 40 μm. Red arrow indicates an area with protein deposition mimicking the histologic findings in myeloma kidney. (F) Complete blood count (CBC) of peripheral blood samples collected from moribund mice and age-matched control mice. (G) Clonality analysis of VQ1 and VQ2 CD138⁺ cells using DJ_H recombination polymerase chain reaction (PCR) assay. *P < .05; **P < .01; ***P < .001. Hb, hemoglobin; I.P., intraperitoneal; ns, not significant; RBC, red blood cell; WBC, white blood cell.