Pre-neoplastic Eμ-myc/Suz12^Plt8/+ mice have an expanded B-lymphoid compartment. (A) Automated enumeration of peripheral blood leukocytes from preneoplastic Eμ-myc (n = 17), Eμ-myc/Bmi1^+/− (n = 8), and Eμ-myc/Suz12^Plt8/+ (n = 12) mice. Immunophenotypic characterization of B-lymphocyte subsets from the (B) peripheral blood, (C) bone marrow, and (D) spleen of preneoplastic Eμ-myc, Eμ-myc/Bmi1^+/−, and Eμ-myc/Suz12^Plt8/+ mice. Data represent mean ± standard deviation. One-way analysis of variance followed by Tukey’s post hoc test was used for pairwise comparisons (*P < .05; **P < .01; ***P < .001). Cell surface markers used to define B-cell subsets are as follows: BM pro-B, B220⁺CD19⁺c-Kit⁺IgM⁻IgD⁻; BM pre-B-II, B220⁺CD19⁺c-Kit⁻CD25⁺IgM⁻IgD⁻; BM pro + pre-B, blood sIg⁻ B, or spleen pre-B, B220⁺CD19⁺cKit⁻IgM⁻IgD⁻; spleen immature B, B220⁺CD19⁺c-Kit⁻IgM⁺IgD⁻, BM sIg⁺; spleen mature B, B220⁺CD19⁺c-Kit⁻IgM⁺IgD⁺.