Inhibition of apoptosis accelerates plasmacytomagenesis. Kaplan-Meier survival curves in cohorts of (A) bim^−/−v-abl (n = 24; P < .0001); (B) mcl-1/v-abl (n = 39; P = .013); and (C) bcl-2/v-abl (n = 47; P = 0.0002) mice and their v-abl littermates (n = 18, 39, and 57, respectively). (D-F) Histological analysis of moribund mice. H&E-stained sections from (D) a mesenteric lymph node tumor showing cells of classic plasmacytoma morphology (400× magnification) and (E) the kidney of a plasmacytoma-bearing mouse, showing the typical myeloma kidney characteristics, namely protein deposits and neutrophil infiltration in the tubules (200× magnification, photographed using a compound microscope; Axioplan 2; Zeiss). (F) H&E-stained sections of the organs from moribund v-abl (n = 10) and bim^−/−v-abl (n = 12) mice were scored blind for the degree of disease infiltration on a scale of 0 to 3 (with 3 being 100% of the organ affected). Mean ± SEM, *P < .05, **P < .01, Student t test. (G) Analysis of plasmacytoma clonality by serum gel electrophoresis. In most cases a single paraprotein (arrowed) is apparent (compare with serum from WT); however, bim^−/−v-abl #149 is biclonal.