Parasites, Cancer, Genetics ...Oh My

Cholangiocarcinoma genes found through parasite research

(RxWiki News) While parasites in raw fish increase the risk for bile duct cancer in Southeast Asia, it may not be the cancer's most common cause. Insights into the cancer's genetic mutations apply a lot more broadly.

Genetic sequencing was used to look at several patients in Thailand with bile duct cancers, and out of the total number of mutations, 15 were found to be important for the cancer's origin.

Several genes were new finds for bile duct cancer.

"Eating raw meat may carry health risks."

Researchers collaborating between Duke University's Singapore branch and the Khon Kaen University of Thailand isolated several new genes with a direct link to bile duct cancer, MLL3, ROBO2, and GNAS.

This research adds to the basic understanding of this cancer, as well as others which share these genetic mutations.

Most theories behind the relationship between the worm-like parasite, known as a liver fluke, and cancer focus on the role of long-standing inflammation in causing cells to go haywire.

Chemicals secreted by the worm to avoid detection by the immune system could also play a role.

The research team was led by Bin Tean Teh, MD/PhD and director of Duke Singapore's NCCS-VARI Translational Cancer Research Laboratory.

"This discovery adds depth to what we currently know about bile duct cancer," said Dr. Teh.

"More important is that we are now aware of new genes and their effects on bile duct cancer, and we now need to further examine their biological aspects to determine how they bring about the onset of cholangiocarcinoma."

The published findings were the result of over two years of teamwork between the universities in Singapore and Thailand, with scientists spending time in their counterpart's country, including both laboratory and fieldwork.

Some of the first observations are that the bile duct cancers share more similarities to pancreatic cancer than previously believed.

In total, eight confirmed cases of parasite-associated bile duct cancer were genetically sequenced, both the tumor and again with normal tissue.

While the total number identified was 206 mutations in 187 genes, each of the eight cases had about 26 mutations, and common mutations that several tumors shared were in seven genes (TP53, SMAD4, KRAS, RNF43, NDC80, ROBO2, GNAS).

The study was published online on May 6, 2012 in the journal Nature Genetics.

Researchers stated no financial conflict of interest.

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Review Date: 
May 15, 2012