A recent review reported that although G-CSF treatment minimally increases the risk of leukemia in MDS patients and those with severe AA, a causal relationship between G-CSF treatment and risk of leukemia could not be entirely excluded [18]; therefore, we did not use G-CSF in the present study, which might explain why none of the patients developed clonal disease. This evidence concerns the gene CSF3 and myelodysplastic syndrome.