Noninvasive Stool Test for Colorectal Cancer Unaffected by Medications, Lifestyle Factors and Other Variables
- Patients did not have to adjust lifestyle or common drugs for this test.
- Age affected four methylation markers studied, but to different extents.
- Selecting optimal methylation markers may minimize false positives.
CHICAGO — Research on an investigational DNA methylation test for colorectal cancer demonstrated that the only clinical variable that influenced test results was age, according to results presented at the AACR Annual Meeting 2012, held here March 31 – April 4.
“There was a progressive increase in background methylation levels that varied widely between methylation markers tested as a patient aged,” said David Ahlquist, M.D., professor of medicine and a consultant in gastroenterology and hepatology at the Mayo Clinic in Rochester, Minn. “For example, median background methylation levels of the TFPI2 gene increased 49 percent in patients from age 50 to age 80, whereas levels for the BMP3 gene increased by only 0.2 percent across this age range.”
His group at the Mayo Clinic, in collaboration with Exact Sciences, developed the multimarker molecular stool test, which is highly sensitive to the critical cancer screening targets of early-stage cancers and precancerous adenomas, he said.
“This test, if broadly applied, should have a very important impact on reducing both the mortality and incidence of colorectal cancer,” Ahlquist said.
The researchers examined common patient variables, including age, sex, race, alcohol consumption, tobacco use, body mass and medication use in 500 patients undergoing screening colonoscopy or polyp follow-up. Patients had a normal colonoscopy in the last three years.
With the exception of age, none of the variables influenced test results, nor did family history of colorectal cancer or polyps or personal history of polyps. These results mean that “patients don’t have to change their lifestyle to have this test,” Ahlquist said. “That was important from a patient-friendly standpoint for a test like this and could benefit compliance.”
Researchers have selected the two markers least affected by age for further test development and validation based on these study results.
“If we can minimize the false positives, that will reduce the cost of the whole screening program by avoiding unnecessary colonoscopies,” Ahlquist said.
The screening test is currently undergoing FDA validation in a multicenter study in the United States and Canada, which is expected to be completed in the fall. The Mayo Clinic and Ahlquist have a financial interest in the technology referenced in this announcement.
Press registration for the AACR Annual Meeting 2012 is free to qualified journalists and public information officers: www.aacr.org/PressRegistration.
About the AACR
Founded in 1907, the American Association for Cancer Research (AACR) is the world’s first and largest professional organization dedicated to advancing cancer research and its mission to prevent and cure cancer. AACR’s membership includes 34,000 laboratory, translational and clinical researchers; population scientists; other health care professionals; and cancer advocates residing in more than 90 countries. The AACR marshals the full spectrum of expertise of the cancer community to accelerate progress in the prevention, biology, diagnosis and treatment of cancer by annually convening more than 20 conferences and educational workshops, the largest of which is the AACR Annual Meeting with more than 18,000 attendees. In addition, the AACR publishes seven peer-reviewed scientific journals and a magazine for cancer survivors, patients and their caregivers. The AACR funds meritorious research directly as well as in cooperation with numerous cancer organizations. As the Scientific Partner of Stand Up To Cancer, the AACR provides expert peer review, grants administration and scientific oversight of individual and team science grants in cancer research that have the potential for patient benefit. The AACR actively communicates with legislators and policy makers about the value of cancer research and related biomedical science in saving lives from cancer.
For more information about the AACR, visit www.AACR.org.
In Chicago, March 31 – April 4: