Epstein-Barr Virus (EBV) is a common virus in the United States, however many people do not show symptoms throughout their lives. Although this virus does not directly cause cancer, infection with this common herpes virus increases risk of some cancers such as lymphomas. Furthermore, an increased risk of other types of cancer, including nasopharyngeal and stomach cancers, has been associated with EBV infections. A new drug was tested on mice which inhibited tumor development, thus it may be useful in treating malignancies in EBV-positive patients. In addition, in treated mice, the drug counteracted the cancer-promoting mechanisms by certain proteins. The drug has potential both as a single agent and in combination with other cancer therapies, such as immune system boosting therapies.