Ultra-sensitive new blood test could locate ‘undetectable’ ovarian cancer

Cancers previously thought undetectable could be identified using a new blood test developed by a team in America.

When tumours appear in the body, they release tell-tale substances that circulate in the blood and can be picked up by doctors.

Using a technique capable of pinpointing individual molecules of some otherwise hidden proteins in blood samples, scientists hope to create a new, ultra-sensitive means of identifying cancer.

In their initial studies, the team from Johns Hopkins University found proteins in patients with ovarian cancer that were not present in other people.

Among the substances they detected was mutant p53 – a well known protein linked to tumours that had never before been found in blood.

This is likely because current methods are not able to capture its incredibly low blood concentrations.

The scientists also found evidence of PD-L1, a chemical marker found on the surface of some cancer cells that has already proved an effective target for cancer therapies.

If PD-L1 can be identified at low levels early on, the scientists think this could speed up these treatments.

Along with picking up on previously hidden substances, the test also identified cancer-related molecules screened for in conventional tests.

Terming their new approach single-molecule augmented capture (SMAC), the researchers now want to see their test developed to a level at which it can be made commercially available.

“With SMAC, we have brought single-molecule imaging into the clinical arena,” said Chih-Ping Mao, one of the two graduate students who developed the test. By visualising and examining individual molecules released from diseased cells into the blood, we aim to detect diseases more accurately and gain new insights into their mechanisms.”

The team presented their research at the Biophysical Society Annual Meeting in Baltimore.

There are around 7,400 new ovarian cancer cases diagnosed in the UK every year, and these numbers are expected to grow significantly in the coming decades.

Excitement has grown in recent years at the prospect of more advanced screening techniques, as most British women are currently diagnosed after the cancer has already spread.

“This piece of research sounds promising,” said Cary Wakefield, chief executive at Ovarian Cancer Action.

“If we are to make a major difference to ovarian cancer survival rates we must develop a screening tool that would catch the disease in its very earliest stages, or better still, before it even develops.

“It is vital we diagnose and treat the disease in its earliest stages to give every woman the best chance of survival.”