The thymidine synthetic nucleoside analogue bromodeoxyuridine (BrdU) has a long, colorful history of repeated use in molecular and cytokinetic studies, as detailed in reviews by Vanderlaan and Dolbeare (1,2). Because BrDU is only incorporated into newly synthesized DNA in actively replicating S-phase cells, it allows for accurate and comprehensive quantitation of the pattern, rate, and progression of cell proliferation.
