CD34 and myelodysplastic syndrome: To assess whether del(5q) gene expression may be affected by mechanisms other than coding or splice site DNA mutations (i.e., mutations in non-coding DNA or epigenetic alterations), we compared the mRNA levels of 28 del(5q) genes in CD34+ purified cells from 6 MDS patients with del(5q), 20 MDS patients without del(5q), and 6 normal donors using the Affymetrix U133plus2 array.