Methylated DNA Blood Test Detects Colon Cancer

"The presence of methlated Septin 9 DNA in blood is a marker suited as an excellent population screening tool to identify a large number of asymptomatic cancers,” said Catherine Lofton-Day, Ph.D., vice president, molecular biology, at Epigenomics. "A blood-based screening assay will be more patient-friendly than the conventional colorectal cancer screening tool, which requires patients to collect and submit fecal samples for fecal occult blood testing--a considerable obstacle to patient compliance.”

The data came from two independent studies that determined Septin 9 levels in a total of 1,500 patients in three distinct categories. One group was known to be free from colon cancer after a colonoscopy. A second group included people with noncolorectal cancers and other noncancerous conditions, and a third group consisted of patients with a confirmed diagnosis of colorectal cancer. In an initial study of 501 samples, 57% of the colorectal cancers were detected. After validating the Septin 9 assay among the three known-status groups in a set of several hundred samples, Dr. Lofton-Day and colleagues predicted the diagnosis of colorectal cancer in an independent set of 790 patients. In this study the detection rate for all colorectal cancers was 50% (104 detected in 209 cases). The false-positive rate for both studies was 4-6%.

"Different stages of colorectal cancers were detected with similar sensitivity, and detection was not affected by location of the tumor in the colon,” explained Dr. Lofton-Day. "This is a reliable, noninvasive method to detect many patients with colorectal cancer who show little or no symptoms.”

The test to identify methylated Septin 9 DNA in blood is not intended to replace periodic colonoscopy or sigmoidoscopy screening but for use as part of routine yearly check-ups. Epigenomics has validated a panel of DNA methylation markers for incorporation into a colorectal cancer screening test in three large clinical studies involving about 2,000 patient samples. The first marker from the panel has been exclusively licensed to Roche Diagnostics (Basel, Switzerland).



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