Katie Couric, coanchor of NBC's "Today Show," has used her high visibility to draw national attention to colorectal cancer— the disease that killed her husband in 1998 but is treatable if caught early. Out of the public eye, scientists have been striving for more-accurate, noninvasive techniques to screen for colorectal cancer.
The most common clinical test looks for blood in a patient's feces, but this method has notable flaws. It catches just 30 to 40 percent of colorectal cancers and sounds a false alarm for 5 to 10 percent of people screened. Alternative tests look for cancer-causing mutations in the DNA of cells shed from the colon and rectum into feces. But most of these tests scan for mutations in just one of several relevant genes.