The Sample and Molecular Core (Core B) has the following functions: 1. Develop and maintain a repository of blood and bone marrow specimens, including intact cells, serum, cellular DMA, RNA, and protein, from patients with MDS receiving care or evaluation at M.D. Anderson Cancer Center. 2. Distribute samples from MDS patients and normal "controls" to MDS P01 investigators. 3. Maintain a comprehensive, prospective, interactive sample database showing type (at diagnosis, at AML progression etc) and characteristics (DNA, RNA etc) of available MDS samples and of their subsequent disposition. 4. Facilitate intra- and extra- MDS P01 collaborations through sharing of blood and marrow resources. 5. Ascertain the incidence of NRAS, KRAS2, and PTPN11 mutations in patients at diagnosis and every 3 months thereafter. 6. Evaluate the possibility that mutations in PTPN11, RAS, and FLT3 can be used to quantify disease burden in MDS. 7. Measure biochemical endpoints of targeted therapeutics (in particular R115777) and correlate these pharmacodynamic data with responses to therapy given in Project 1.