RASA3 and myelodysplastic syndrome: Adult naïve SCID mice intraperitoneally injected with 107 splenocytes isolated from these SCID-Rasa3−/− mice did not develop a similar proliferative disorder within 4 months after injection, suggesting the presence of a preleukemia rather than a leukemia in these 4 SCID-Rasa3−/− mice (data not shown).