MicroRNAs are a class of ~22 nucleotide RNA molecules with roles in diverse biological processes. Here I focus on two microRNAs, miR-155 and miR-125b, and reveal pathways by which their dysregulation leads to myeloproliferative disorder (MPD) and leukemia, respectively. I begin by searching for miR-155 target genes relevant to MPD. By writing an algorithm to search microarray data for predicted microRNA target genes, I identified 89 candidate target genes for miR-155 in myeloid cells. Literature...