Mammalian cell cycle control and signal transduction pathways are usually perturbed in the genesis and progression of cancer, causing the cancerous cell to be locked into an active proliferative state. Increased understanding of these processes has led to the development of pharmaceutical agents designed to intervene at specific molecular steps involved in carcinogenesis. These agents include inhibitors of cell cycle progression, inhibitors of tyrosine kinase receptors and inhibitors of other molecules involved in intracellular signal transduction such as farnesyltransferase. It is hoped that such agents will, due to their specificity, be both more effective and less toxic than conventional nonspecific chemotherapy. At the 91st Annual Meeting of the American Association for Cancer Research (AACR) [San Francisco, US; April 2000], some encouraging results in this field were presented, including Glaxo Wellcome's GW 8510, a potential preventative treatment for chemotherapy-induced alopecia, data from Roche's new cell cycle inhibitor RO 317453 and an update on Novartis' tyrosine kinase inhibitor STI 571.