MDS, or Myelodysplastic Syndrome, is a preleukemic blood disorder. In this case, the mutated cells live along side normal cells. But once the number of mutated cells grows to the point where they begin to crowd out the normal cells, leukemia develops. Once that happens, life expectancy is about 3 years. There are new therapies to stem the tide of this disease, and research is underway via clinical trials to improve treatment