Breakthrough in cancer research: Northwestern joins team to detect cancer in early stages


Linus Höller / The Daily Northwestern

Feinberg Professor Wei Zhang and his team found a non-invasive method of detecting cancer early on – with much higher accuracy than existing methods.

Linus Höller, Reporter

A team of researchers proved the effectiveness of a novel method to detect liver cancer with a small blood sample, a victory in the ongoing battle against the disease.

The method works by looking for a specific biomarker: 5-hydroxymethylcytosines. This molecule exists in all humans in certain patterns because it regulates gene expression in DNA. However, patterns of 5-HMC at certain loci differ between cancer cells and normal cells. Finding these altering patterns allowed the researches to detect cancers very early on. Wei Zhang, an associate professor of preventive medicine at Feinberg, co-authored the paper about their research, published in Gut, a journal by the British Society of Gastroenterology.

For one, the current standard for diagnosing liver cancer is a biopsy, in which a piece of tissue is extracted from the patient’s liver. The new method requires only a small blood sample, no more than five milliliters, Zhang explained.

“There are obvious benefits over existing methods,” Zhang said. “We would be able to detect as little as 100 cancer cells from just a few milliliters of blood.”

After drawing blood, the plasma is centrifuged to separate out the circulating cell-free DNA – the genetic material released into the bloodstream by damaged cells, such as cancer cells.

After separation of the DNA, a chemical reaction – developed by Prof. Chuan He of The University of Chicago – inds which fragments of the DNA have 5-HMC molecules. The DNA is then sequenced using next generation sequencing, and the collected data runs through a computer to look for deviations from the normal 5-HMC patterns.

“You could have your blood taken at a lab and get the results just a few days later,” Zhang said.

A somewhat comparable method already exists, which works by looking for alpha-fetoprotein in the patient’s bloodstream. However, Zhang said he sees several problems with this method.

“For one, proteins are not stable,” he said. This means that the molecules are susceptible to many changes, such as being digested by the liver. The results of an AFP test can also be affected by other factors, such as chronic diseases. The new method using 5-HMC avoids these problems.

Zhang and his colleagues are currently focused on the application of 5-HMC patterns to detect cancers in other parts of the body and even other diseases, such as diabetes. Though 5-HMC is the biomarker in all of them, the deviating patterns exist at different loci, he said. This means that while liver cancer may be seen by a different pattern of 5-HMC on a certain region of the genome, a different disease such as multiple myeloma will show up at a different part of the DNA, Zhang said.

The team of researchers will further consolidate their findings, and Zhang said he hopes to enter FDA trials and apply his research to general use as soon as possible. If all goes according to plan, Zhang anticipates the test may be available to the public in as little as three or four years.

Zhang said he enjoys research for the sake of knowledge, but saving lives is his priority.

“I think this is my most impactful paper,” he said. He smiled in jest. “Finally, I am doing something useful.”

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