The considerable progress in our understanding of the complex cellular, molecular, and genetic mechanisms underlying tumorigenesis over the last decade has fostered the development of novel and improved targeted therapies in cancer intervention. Because these therapies specifically interfere with signaling pathways essential for tumor cell proliferation, survival, and migration, they may be able to inhibit tumor growth and metastasis effectively, with fewer severe adverse events than seen with current chemotherapeutic interventions that have a narrow therapeutic index and are associated with severe toxic side effects. Monoclonal antibodies and protein tyrosine kinase inhibitors represent two classes among these promising new therapeutic interventions. This review discusses the advantages, limitations, and potential of monoclonal antibodies and protein tyrosine kinase inhibitors, and offers a perspective on the requirements and goals likely to propel the design of additional anticancer agents in the future.