A new blood test is very promising for finding cancer-related microRNA in the blood before a tumor develops in the colon. The test results are exciting and promising because this simple blood-based test examines levels of a single microRNA, which is a small RNA molecule that can be readily identified in a wide variety of body fluids—including blood.
This seminal study, published in the Journal of the National Cancer Institute (2013; doi:10.1093/jnci/djt101), involved several hundred patients with colorectal polyps and cancers. Investigators reported that measuring levels of miR-21 in the blood can accurately identify up to 92% of patients with colorectal cancer. Even more importantly, not only is this test good as a noninvasive method for identifying patients who already had colorectal cancer, but it can accurately identify up to 82% of patients with advanced colonic polyps, which have the highest risk for developing into colorectal cancers several years later in life.
“The development of this biomarker is highly encouraging because high mortality rates associated with colorectal cancer is a consequence of late detection of this disease, underscoring the need for improved early detection, prevention, risk assessment, and intervention,” said principal investigator Ajay Goel, PhD, director of Epigenetics and Cancer Prevention at Baylor Research Institute in Dallas, Texas. Early detection of advanced colorectal polyps and cancers is considered the most relevant target for screening strategies and the best approach to improving survival of these patients.
“This blood-based test could be transformative in how we screen patients for colorectal cancer; it would save lives and could result in major savings of health care dollars,” said Michael Ramsay, MD, president of Baylor Research Institute.
While more testing needs to be done, the findings were enough to warrant an editorial in the highly regarded Journal by Heinz-Josef Lenz, MD, associate director for clinical research at the University of Southern California’s Norris Comprehensive Cancer Center in Los Angeles. “MiR-21 may not be ‘just another brick in the wall,’ but rather may be the keystone leading to a molecularly justified, miRNA-based biomarker era in colorectal cancer,” Dr. Lenz said in the Journal.