Although the expression and signaling of TLRs is known to be increased on the CD34+ cells of MDS patients, for example, as well as the leukemia cells in various myeloid and lymphoid cancers, it is not known whether other cell types within the bone marrow microenvironment (hematopoietic and stromal) also display aberrant TLR signaling, and what role this non-autonomous signaling may play in the pathogenesis of the disease. The gene discussed is CD34; the disease is leukemia.