Viral-based gene delivery and regulated gene expression for targeted cancer therapy

Importance of the field. Cancer is both a major health concern and a care-cost issue in the US and the rest of the world. It is estimated that there will be a total of 1,479,350 new cancer cases and 562,340 cancer deaths in 2009 within the US alone. One of the major obstacles in cancer therapy is the ability to target specifically cancer cells. Most existing chemotherapies and other routine therapies (such as radiation therapy and hormonal manipulation) use indiscriminate approaches in which both cancer cells and non-cancerous surrounding cells are treated equally by the toxic treatment. As a result, either the cancer cell escapes the toxic dosage necessary for cell death and consequently resumes replication, or an adequate lethal dose that kills the cancer cell also causes the cancer patient to perish. Owing to this dilemma, cancer- or organ/tissue-specific targeting is greatly desired for effective cancer treatment and the reduction of side effect cytotoxicity within the patient. Areas covered in this review: In this review, the strategies of targeted cancer therapy are discussed, with an emphasis on viral-based gene delivery and regulated (gene expression. What the reader will gain: Numerous approaches and updates in this field are presented for several common cancer types. Take home message: A summary of existing challenges and future directions is also included.