Scientists have found a new method to detect genetic variations that initiate colon cancer could be readily used for non-invasive colon cancer screening.
Bettina Scholtka, Ph.D., assistant professor in the Department of Nutritional Toxicology at the University of Potsdam in Nuthetal, Germany, said that tumour cells are released into stool from the surface of precancers and early-stage colon cancers, but detecting a cancer-initiating genetic mutation among a large quantity of normal DNA from a patient’s stool is like looking for a needle in a haystack.
Scholtka said that by combining for the first time locked nucleic acid-based, wild-type blocking polymerase chain reaction and high-resolution melting, we were able to achieve the desired sensitivity.
Scholtka and colleagues used 80 human colon tissue samples representing cancers and precancers to detect genetic variations using a combination of two techniques: The first technique — locked nucleic acid (LNA)-based, wild-type blocking (WTB) polymerase chain reaction — suppressed normal DNA present in large quantities in the sample; and the second technique — high-resolution melting (HRM) — enhanced the detection of genetic variations.
The researchers were able to detect APC variations in 41 of the 80 samples. They were also able to detect previously unknown variations in APC. In contrast, the routinely used technique called direct sequencing could detect variations only in 28 samples.
They then analyzed 22 stool samples from patients whose colon tissues had APC variations, and nine stool samples from patients whose colon tissues did not have APC variations, as controls. They were able to detect APC variations in 21 out of 22 samples.
The study has been published in Cancer Prevention Research.