Published online Sep 21, 2016. doi: 10.3748/wjg.v22.i35.7999
Peer-review started: May 3, 2016
First decision: June 20, 2016
Revised: July 12, 2016
Accepted: August 10, 2016
Article in press: August 10, 2016
Published online: September 21, 2016
Gastrointestinal cancer has been one of the five most commonly diagnosed and leading causes of cancer mortality over the past few decades. Great progress in traditional therapies has been made, which prolonged survival in patients with early cancer, yet tumor relapse and drug resistance still occurred, which is explained by the cancer stem cell (CSC) theory. Oncolytic virotherapy has attracted increasing interest in cancer because of its ability to infect and lyse CSCs. This paper reviews the basic knowledge, CSC markers and therapeutics of gastrointestinal cancer (liver, gastric, colon and pancreatic cancer), as well as research advances and possible molecular mechanisms of various oncolytic viruses against gastrointestinal CSCs. This paper also summarizes the existing obstacles to oncolytic virotherapy and proposes several alternative suggestions to overcome the therapeutic limitations.
Core tip: Cancer stem cells (CSCs) are derived from tumor cells, which are responsible for tumor relapse and drug resistance. The high incidence, lethality, relapse and drug resistance of gastrointestinal cancer requires a novel therapeutic strategy against CSCs. Oncolytic viruses hold much promise because they kill tumor cells but are minimally toxic to normal cells. Isolation and identification of CSC markers for treatment of gastrointestinal cancer will benefit the engineering of oncolytic viruses and targeting anti-tumor effects. This paper reviews research on oncolytic viruses against gastrointestinal CSCs, and toxicity and immunological barriers to oncolytic virotherapy, and proposes alternative strategies.