The present invention features methods of treating a cancer in a subject by administering an effective amount of a beta-lactone to the subject. The invention also features methods of inhibiting angiogenesis in a subject by administering an effective amount of an inhibitor of fatty acid synthase to the subject. These methods can be used to treat a variety of cancers and other diseases and conditions. The invention also features methods of identifying beta-lactones and other compounds that can be used in the methods of the invention for the treatment of tumors, inhibition of angiogenesis, and the treatment of diseases and conditions that involve pathological angiogenesis. The invention also features methods of synthesizing beta-lactones and features novel beta-lactone compounds.