Researchers have found new techniques to spot certain gene variations that have been linked to colon cancer, and they say their new findings may soon allow doctors to identify the disease in the very first stages, potentially saving patients’ lives.

The study, published in Cancer Prevention Research, was carried out by Bettina Scholtka, assistant professor at the University of Potsdam in Germany, and colleagues.

According to the researchers, two genes are most frequently mutated in patients with colorectal cancer; 60% of patients have a mutated APC gene and 40% of patients have a mutated KRAS gene.

Until now, however, finding these mutations has been tricky, as Scholtka explains:

“Tumor 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.”

Because precancer cells carrying the genetic mutations are regularly passed through the stool, Scholtka says detecting these cells in stool samples is better than in blood. She notes that the cells can only be detected in blood once the cancer has reached a later stage.

To test their method, the researchers used a combination of two techniques to analyze genetic variations within 80 cancerous and precancerous human colon tissue samples:

  • Locked nucleic acid (LNA)-based, wild-type blocking (WTB) polymerase chain reaction, which suppressed normal DNA present in large quantities, and
  • High-resolution melting (HRM), which enhanced the detection of genetic variations.

Through these methods, the researchers detected APC variations in 41 of the 80 samples and also identified previously unknown variations in APC. The currently used technique – direct sequencing – only detected variations in 28 of the samples.

When the researchers then analyzed 22 stool samples from patients with APC variations in their colon tissues (and nine control stool samples without APC variations), they successfully detected APC variations in 21 out of the 22 samples.

Additionally, the team was able to detect KRAS variations in 20 human colon tissue samples, demonstrating that their technique can also identify variations in non-APC genes.

Bettina Scholtka says that “the extremely high sensitivity of this technique allows us to find very low amounts of different types of the cancer-initiating mutations in patients’ stool samples.”

Scholtka adds:

By using our technique for examining a selection of genes that become mutated during the process of colon cancer formation, it is possible to detect the very first stage of colon cancer and even precancers in a stool sample.”

The researchers say that prevention and early detection of cancer is a goal of the World Health Organization (WHO), and they note that the removal of precancer lesions has been shown to reduce cancer incidence in the case of colorectal cancer.

Additionally, they say there is a need for sensitive tests for those people who refuse colonoscopy screening.

“It will be possible,” says Scholtka, “to prevent cancer in many cases by removing the precancerous lesions after early detection.”