Urinary PGE-M in colorectal cancer: predicting more than risk?

Progress in cancer chemoprevention has been hindered by a lack of validated biomarkers of risk and interventive response. The identification of accurate, reliable, and easily measurable risk and response biomarkers within the field of cancer prevention could dramatically alter our approach to the disease. Colorectal cancer is associated with substantial morbidity and a limited 5-year survival rate for late-stage disease. The identification of biomarkers to predict (i) those most at risk of clinically significant colorectal neoplasia in conjunction with or building upon current risk models and/or (ii) those most likely to respond to potential colorectal chemopreventive agents, such as aspirin and NSAIDs, would significantly advance colorectal cancer risk management. Urinary PGE-M is an established indicator of systemic prostaglandin E2 production and has previously been demonstrated to predict risk of advanced colorectal neoplasia in a handful of studies. In the July 2014 issue, Bezawada and colleagues confirmed those earlier risk associations and demonstrated that PGE-M can also predict responsiveness to aspirin/NSAIDs in a small subset of women undergoing lower endoscopy in the Nurse's Health Study. PGE-M has the potential to define subsets of the population that may derive greater chemopreventive benefit from NSAIDs, as well as the potential to optimize the use of expensive and/or invasive screening tests. Additional larger and more diverse prospective studies meeting the criteria for phase IV biomarker studies are needed to advance the development of PGE-M as a noninvasive biomarker of both risk and chemopreventive response in populations at risk for colorectal cancer.