Monitoring tumour DNA shows promise for following progress of disease.
A blood test for DNA shed by dying tumour cells might one day be used to track a patient's response to therapy, results from a pilot study in breast cancer suggest. The technique would provide an alternative to invasive biopsies that retrieve tumour tissue for analysis.
The study tracked free-floating tumour DNA isolated from the blood of 30 women with advanced breast cancer. The results indicate that the quantity of tumour DNA in the blood could reflect the extent of a patient’s cancer1.
The results will need to be replicated in a much larger, randomized trial before the technique can enter routine clinical use, says Carlos Caldas at the Cancer Research UK Cambridge Institute, one of the leaders of the work. But the results of the current study, the largest of its kind, are cause for optimism that the technique could quickly and easily monitor the responses of patients to treatment, he adds, particularly when repeat biopsies would be prohibitively expensive and invasive.
“This is a powerful technology,” agrees Daniel Haber, a cancer researcher at the Massachusetts General Hospital Cancer Center in Boston, who was not involved with the study. “It can be very scalable, inexpensive, and useful.”
Needle in a haystack
Depending on the extent of the disease, tumour DNA can make up anywhere from less than 1% to 50% of the cell-free DNA found in blood plasma, says Caldas.
In essence, the assay is analogous to the new wave of prenatal genetic tests that use tell-tale markers to find fetal DNA circulating in the mother’s blood. In the case of the tumour study, the researchers quantified the amount of tumour DNA in the blood by looking for cancer-associated mutations, focusing primarily on two genes, TP53 and PIK3CA...
(Excerpt) Read more at nature.com ...
