London, July 4 : Researchers from Massachusetts General Hospital Cancer Centre in Boston are developing a blood test that would help in monitoring lung cancer progression by detecting tumour cells circulating in the bloodstream.
With the new non-invasive technique, doctors would be able to perform genetic tests on these spreading cancer cells and help them decide the treatment that would be most effective in inhibiting tumours.
"If they can scale this up for commercial use, it could be a marked breakthrough," Nature quoted Joan Schiller, an oncologist at the University of Texas Southwestern Medical Center in Dallas, as saying
Tumour cells can enter the bloodstream during even the earliest stages of cancer. Although these cells may not promote new cancers elsewhere in the body, researchers have observed that an increase in the total number of circulating tumour cells can lead to poorer diagnosis in some forms of the disease.
In 2007, lead researcher Daniel Haber developed a new way of isolating circulating tumour cells with help of a device that thrusts blood samples through tiny channels.
These tiny channels contain microscopic columns coated with an antibody for a protein released by epithelial cells. Tumour cells hook onto the columns, allowing them to be separated from the blood.
In the present study, involving 27 lung cancer patients, Haber's team isolated the circulating tumour with the help of their device.
They are now using those tumour cells to carry out genetic tests in patients with non-small-cell lung cancer. Some non-small-cell lung cancer tumours have a mutation in a protein called epidermal growth factor receptor.
The mutation makes the protein vulnerable to drugs that inhibit receptor and stall tumour progression. Currently used technique for lung tumour biopsies involve inserting fine needle into the tumour and drawing off a small number of cells.
"It's not just a needle stick, it's an invasive procedure - it's painful," said Haber.
They researchers could isolate an average of about 100 cells for every millilitre of blood they analysed.
While comparing the genetic makeup of the circulating tumour cells with the biopsies, the researchers found that analysis of the circulating tumour cells matched the biopsy 92pct of the time.
Haber said that the new technique not quite ready for clinical use.or now, the procedure is slow and laborious, and the collaborators are working to optimize the device for high-throughput use.
The results are published in the New England Journal of Medicine.