The present invention relates to compositions and methods for cancer diagnostics and therapeutics, including but not limited to, HIP1 cancer markers. In particular, the present invention provides compositions and methods of using HIP1 in the diagnosis and treatment of epithelial cancers. The present invention thus provides improved compositions and methods for diagnosing and treating some of the most common cancers (e.g., prostate and colon cancers). The present invention additionally provides drugs active against HIP1 and methods for screening for such drugs.