The present invention is directed in part towards methods of modulating the function of serine/threonine protein kinases with quinazoline-based compounds. The methods incorporate cells that express a serine/threonine protein kinase, such as RAF. In addition, the invention describes methods of preventing and treating serine/threonine protein kinase-related abnormal conditions in organisms with a compound identified by the invention. Furthermore, the invention pertains to quinazoline compounds and pharmaceutical compositions comprising these compounds.