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Saturday, Oct. 22, 2011
Passed gas may yield colorectal cancer clue
By JUN HONGO
Studies by Japanese researchers on intestinal gas and its sulfur-containing compounds may help develop new measures to detect colorectal cancer by examining flatulence, according to a recently published article in the U.K. magazine Nature Review magazine.
The studies will likely save patients a lot of hardship — and medical bills.
Screening for the cancer today is conducted through measures such as injecting a barium enema or inserting a colonoscope into the anus.
A team led by Shinya Yagi, an associate professor of quantum engineering at Nagoya University, found through studying flatulence omissions of colorectal cancer patients that they are likely to have 10 times more of a gas element called methyl mercaptan than that of a healthy person.
The research took 22 samples of intestinal gas from patients and 16 samples from those without cancer. Yagi and his team collected samples in special bags containing metal particles that were designed to absorb the consisting elements of gas. The collection bags were then taken to the Synchroton Radiation Center at Hiroshima University for tests.
The research revealed that cancer tumors secrete gaseous sulfur-containing compounds, and the amount of methyl mercaptan tended to grow for patients in later stages of colorectal cancer.
The screening method is not yet ready for practical use since at this point it must undergo further testing to refine the methods, Yagi told The Japan Times on Friday.
"The key thing to do is gather the gas first thing in the morning, when it is the most condensed. That will result in finer results," he said of his research. The amount of methyl mercaptan will not translate directly to the level of bad smell, because flatulence contains other elements that the human nose detects as the smell.
Yagi said the idea for his study came through his research of exhaust gas, such as sulfur oxide. The specialist on nanoparticles was contacted by Nagoya-based dentist Kazue Yamagishi, who was studying the correlation between periodontal disease and foul breath.
The answer was blowing in the wind for both of their projects.
Yagi teamed up with Yamagishi and they began their study in 2005. Their effort was published in GUT, a specialist English medical journal about the digestive system in August this year titled "Generation of gaseous sulfur-containing compounds in tumor tissue, and suppression of gas diffusion as an antitumor treatment."
Nature Review magazine followed it up with an article on Yagi and Yamagishi in October.
According to the U.S. National Cancer Institute, the cause of colorectal cancer, in which cells in the colon or rectum form a tumor, is still unknown. But studies have shown that factors such as age, family history, diet and smoking come into play for one's chances of developing the disease.
Yagi told The Japan Times that proving the correlation between flatulence and cancer scientifically had to go through a variety of procedures, including using laboratory rats.
Naturally, it was also challenging to convince cancer patients to release intestinal gas into a bag.
"We got mixed reactions from the patients and their families as well. Many thought we were joking to be asking them to do such a thing," Yagi said.
Pundits say the technology could eventually be applied to other cancer screenings, including detection of lung cancer from a patient's breath.