PTPN11 mutants E76K, D61V, and D61Y induce hematopoietic progenitor hypersensitivity to GM-CSF. Transduced EGFP⁺ cells were plated in CFU-GM progenitor assays in duplicate in 3 independent experiments. The data are represented as a percentage of maximal colony formation, which is calculated by dividing the number of colonies at each dose by the number of colonies at the maximal GM-CSF concentration (10 ng/mL). Error bars indicate standard error of the mean. Statistical analysis was conducted using random-effects ANOVA to deal with repeated measurements from duplicate plates. (A) E76K vs MIEG3 and WT; ^*P = .0014 for E76K vs MIEG3 and ^*P = .0015 for E76K vs WT; ^**P < .0001 for E76K vs MIEG3 or WT. (B) D61V vs MIEG3 and WT; ^*P < .0001 for D61V vs MIEG3 or WT. (C) D61Y vs MIEG3 and WT; ^*P = .0179 for D61Y vs MIEG3 and ^*P = .02 for D61Y vs WT; ^**P = .0058 for D61Y vs MIEG3 or WT; ^***P < .0001 for D61Y vs MIEG3 or WT.