Decreased numbers of BM B lineage progenitors after Men1 inactivation. (A) BM B lineage progenitors were defined by flow cytometry. Pro-B cells: B220⁺CD43⁺AA4.1⁺CD19⁺; pre-B cells: B220⁺CD43⁻AA4.1⁺sIgM⁻; immature B: B220⁺CD43⁻AA4.1–sIgM⁺. (B) Absolute cell numbers calculated in 2 hind legs. ▵: control CreER^Tm+Men1^+/+; ▴: CreER^Tm+Men1^f/f mice. P values indicate the results of a Student t test (*, statistically significant, P < .05).