MicroRNAs may aid cancer detection

In collaboration with the Press Association

US scientists have found that microRNAs - single strands of genetic material that control whether certain proteins are made - are released into the bloodstream by cancer cells and could therefore be used to detect cancer in its early stages.

A team at the Fred Hutchinson Cancer Research Centre compared blood from mice and humans with advanced prostate cancer with blood from people who were cancer-free.

They measured microRNAs made by the tumours and found that they were able to distinguish between individuals with cancer and those who were free from the disease, based on these measurements.

The amount of tumour-derived microRNAs in the blood was also found to be high enough to enable their use as a biomarker for cancer.

Researcher Dr Muneesh Tewari, an assistant member in the Hutchinson Centre's Human Biology and Clinical Research divisions, commented: "This research shows that microRNAs, which weren't previously thought of as markers of cancer in the blood, are a worthwhile class of molecules to study for the purpose of early cancer detection.

"We were surprised to discover that there are microRNAs in plasma and serum that are not associated with cells and that are not being degraded by enzymes in the blood that would degrade regular RNA."

Scientists are currently unsure of how the cancer-associated microRNAs enter the blood, or of how they are protected from degradation, but laboratory tests have confirmed that they can remain intact even after being subjected to eight freeze/thaw cycles.

Writing in the Proceedings of the National Academy of Sciences, the researchers concluded: "The results presented here establish the foundation and rationale to motivate future global investigations of microRNAs as circulating cancer biomarkers for a variety of common cancers."

They now hope to identify specific microRNAs that are associated with particular forms of cancer and to develop the technology to detect minute amounts of these microRNAs so that the disease could be diagnosed in its early stages.

Read the abstract online

Read the press release online