from The Asahi Shimbun
Researchers have developed a test to detect early-stage colorectal cancer that is quicker and more precise than conventional methods, and requires only a small blood sample.
Led by Takahiro Ochiya, chief researcher of the National Cancer Center’s Division of Molecular and Cellular Medicine, the researchers said the new method could be developed for practical use within a few years. Their findings were published in the online version of British scientific journal Nature Communications.
“The new method is more efficient in detecting colorectal cancer in its early stages, easier to use and higher in precision than conventional methods and thus can reduce patients’ burden,” Ochiya said.
Ochiya and his colleagues focused their attention on particles called exosome, which are secreted by cells. The scientists discovered that exosome secreted by colorectal cancer cells contained certain proteins in higher proportions.
They also developed a method to make the proteins gleam in a blood sample. It requires only 0.005 milliliter of a blood sample to determine whether it contains the proteins, and the biopsy only takes 90 minutes to three hours, the researchers said.
When they tested the method on 194 patients with colorectal cancer, about 50 percent were found to have the proteins in their blood. Among 191 patients without colorectal cancer, only one was positive for the proteins.
The researchers said they will try to detect other proteins that are secreted by colorectal cancer cells to increase the precision of the test.
The number of colorectal cancer patients in Japan has increased to account for the second largest group among cancer patients, next to stomach cancer. It is expected to become the largest group in the near future. Among female cancer patients, colorectal cancer is the largest cause of death.
A fecal test to check the presence of blood has been used as a method to detect colorectal cancer, but only about 4 percent of those whose stool contains blood are found to have developed cancer.
“There is a possibility that (the new method) can also be applied in detecting pancreatic cancer, which is now difficult to detect in its early stages, and for diagnosis of illnesses other than cancers,” Ochiya said.