NB 4 cells were treated with 5 mM valproic acid for 24 hours to induce apoptosis. Apoptosis was measured using annexin V-FITC and propidium iodide (PI) according to the manufacturer's protocol. RNA was also isolated using Trizol. Targets were produced using standard Affymetrix procedures from about 8ug of total RNA. Keywords = Homo sapiens, RNA degradation, apoptosis, microarray