New microRNAs are being described on a weekly basis, and specific microRNAs have been implicated in the pathogenesis of both malignant and non-malignant conditions. Dr. Scott Boyd will begin with an overview of the world of microRNAs - their discovery, current knowledge about their biology, and state-of-the-art approaches for their identification. Dr. George Calin will then focus on the ever-expanding role of microRNAs in leukemogenesis, with examples relevant to AML and CML. Finally, Dr. Kristina Cole will discuss the importance of microRNAs in pediatric solid tumors, with an emphasis on neuroblastoma.