Researchers develop blood test to detect cancer

14 September 2015

A new blood test identifying cancer-specific gene mutations in DNA could drastically change  the way cancer was diagnosed and treated according to researchers.

Researchers from the Royal Brompton Hospital and the National Heart and Lung Institute (NHLI) at Imperial College London hope that the test would one day be available in GP surgeries to provide a diagnosis within days to start treatment earlier than with current practice.

A study led by Eric Lim, consultant thoracic surgeon, involved blood tests from 223 patients and researchers were not told that the patients, who were all pre-surgery for known or suspected lung cancer, had already received a definitive diagnosis.

Researchers extracted DNA from the plasma of the blood and analysed it to identify three common gene mutations.

With the test, researchers correctly identified cancer-specific gene mutations in the DNA of nearly seven out of 10 patients who were later confirmed to have cancer.

The blood of healthy individuals did not normally contain these cancer-specific gene mutations.

The test was not an alternative to a biopsy for all patients, but when a blood test showed a positive result, this could mean the patient would be saved from going through an unnecessary and invasive diagnostic procedure.

Meanwhile, US firm, Pathway Genomics, on Thursday announced that it would soon launch the technology of liquid biopsy- that would detect cancer through analysis of blood samples.

The technology studied gene sequencing to screen blood samples for cancer detection and the introduction of blood tests that detected abnormality in pregnant mothers through DNA blood tests was the trigger point for this new research.

According to financial services firm, Cowen & Co, the new technology would go a long way in cancer screening and would likely exceed $10 billion mark in a year 10 years from now.

The invention, however, had triggered debates as to whether healthy individuals should get unnecessary exposure to DNA tests.

This was not the first controversy surrounding Pathway, against which the US Food and Drug Authority had, in 2010, issued warnings of misuse of genetic testing kits.

Walgreens withdrew Pathway's genetic testing kits from its pharmacies following the warnings.

According to oncologists, such technologies could not be looked at as a whole, until clinical trials had been conducted and approved.

"For any given test, the rate of false positives causing unnecessary alarm and false negatives that provide false security should be known," said Dr Keith Stewart, an oncologist who heads Mayo Clinic's Center for Individualized Medicine, reported.

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