Deletion of Ptpn11 leads to fatal BM failure and loss of HSCs. (A) Kaplan-Meier survival analysis of a cohort of Mx1-Cre;Ptpn11^flox/flox (n = 30) and littermate control (n = 28) mice after pIpC treatment. Ptpn11^Δ/Δ mice have a median life span of 5 weeks; control mice remain healthy for > 10 months. *P < .05, log-rank test. (B) Hematoxylin and eosin-stained sections from humeri of control and Ptpn11^Δ/Δ animals 4 to 5 weeks after receiving their last dose of pIpC. The samples were analyzed using an Olympus BX41 microscope with the objective lens 4×/0.75 Olympus UPlanFL (Olympus). The pictures were taken using Olympus QColor5 and analyzed with acquisition software QCapture Pro v6.0 (QImaging) and Adobe Photoshop 6.0 (Adobe). (C-D) White blood cell count (WBC; C) and hematocrit (HCT; D) of control and Ptpn11^Δ/Δ mice. *P < .05, Student t test. (E) BM cellularity (per 2 hind limbs) in control and Ptpn11^Δ/Δ animals shown as mean ± SEM. *P < .05, Student t test. (F) Absolute number (mean ± SEM). *P < .05, Student t test. LSK, common lymphoid progenitors (Lin⁻ Sca1⁺ c-kit^loIL7Rα⁺), common myeloid progenitors (Lin⁻Sca1⁻c-kit⁺CD34⁺FcγR^lo), granulocyte-macrophage progenitors (Lin⁻Sca1⁻ c-kit⁺CD34⁺FcγR^hi), megakaryocytic-erythroid progenitors (Lin⁻Sca1⁻c-kit⁺CD34⁻FcγR^−/lo) of control (n = 7) and Ptpn11^Δ/Δ mice (n = 7). (G) Absolute number (mean ± SEM). *P < .05, Student t test. SLAM-HSCs from control (n = 3) and Ptpn11^Δ/Δ mice (n = 3).