Scientists develop highly sensitive blood test to detect cancer

Scientists at Stanford University in California have developed a cost-effective and highly sensitive blood test to detect cancer.

Called single colour digital PCR, the test can detect genetic mutations in minute amounts of DNA released from cancer cells into the blood.

According to researchers, the highly sensitive test requires only a fraction of a tube of blood and can detect as few as three mutation-bearing molecules in a single reaction.

According to Hanlee P Ji, associate professor at Stanford, only a handful of blood tests are available for monitoring patient tumours, which are limited to only several types of cancers. "Nearly all cancer patients require monitoring by whole body imaging, which can be costly, complex, and time- consuming,” he said.

Key Highlights

• The new test has the potential to be personalised to recognise mutations unique to any individual cancer.

• It will also enable patients to be monitored at every visit and thus have the potential for quickly tracking cancer growth and spread.

• In comparison to next-generation DNA sequencing, the test would be relatively low cost.

• It will potentially provide an opportunity for universal monitoring of more number of patients than those covered currently.

The Experiment

• The researchers used the test to analyse samples from six patients, among whom five were previously diagnosed with colorectal cancer and one with cholangiocarcinoma or bile duct cancer.

• After generation of customised mutation detection assays, the researchers identified tumour-derived circulating DNA from three out of six patients.

• In one patient, the assay was able to show the presence of three different mutations.

• The three patients, whose samples did not show elevated cancer DNA, were undergoing active treatment at the time of collection.

Comment

The test offers several advantages over other methods of circulating tumour DNA analysis, the main one among which is that it does not rely on pre-amplification, which can introduce errors and biases.

Further, the test is relatively simple to set up and analyse without extensive training and therefore, it can be implemented by anyone, making it highly accessible to any laboratory.

The research was published in a journal called, the Journal of Molecular Diagnostics.