The identification and analysis of tumor suppressors is of major importance for improved diagnosis and treatment of tumors. Bin1 (Box-dependent myc interacting protein 1, also known as SH3P9, amphiphysin II and amphl/amphiphysin-like) is a novel protein that has features of a tumor suppressor. Bin1 interacts with and inhibits the oncogenic activity of the myc oncoprotein that has a major role in many human cancers. The loss of Bin1 may contribute to growth deregulation in cancer cells in carcinoma of the breast, colon, lung, cervix, prostate and liver. Bin1 also interacts with HCV NS5A through its SH3 domain.