To avoid a priori exclusion of lower-risk MDS samples or patient samples with low cell numbers, CD34+ cell injections for different samples ranged from 0.5 × 105 to 1 × 106 cells per recipient mouse, while maintaining the same cell number for all recipients within each experiment (for detailed patient and sample information see Supplementary Table 1). The gene discussed is CD34; the disease is myelodysplastic syndrome.