In an interview with The ASCO Post, 2016 President-Elect of ASCO Daniel Hayes, MD, explained his interest in what he labeled “very exciting technology.”
“Most of the DNA in plasma is normal, coming from white cells. Within that, there’s a small amount of tumor DNA. I have been told that you either have to draw the blood and process it right away, before the white cells start dying and swamp the tumor DNA, or draw it into tubes that contain a fixative that keeps the white cells from dying,” he said.
“The point is, normal DNA can swamp cancer DNA if you don’t process it correctly,” added Dr. Hayes. “The blood samples from BOLERO-2 came from all over the world, and they almost certainly sat around on desk tops before they were spun down.”
“This is important because many researchers have archived samples that we are keeping, but we didn’t think we could use them. In my opinion, since this was feasible, it opens up an enormous opportunity for researchers,” he said. “We want to do this too!”
Dr. Hayes emphasized that the findings have utility in the laboratory world but not yet in the clinic, as the analysis on the effect of these mutations on outcome was exploratory, with very small numbers. “This is nothing to be used clinically,” he remarked. ■
Disclosure: Dr. Hayes reported no potential conflicts of interest.
A plasma-based cell-free DNA test identified mutations in the estrogen receptor 1 gene (ESR1) in 30% of patients from the BOLERO-2 trial of everolimus (Afinitor) plus exemestane, and these mutations were correlated with survival. The results, which support the use of plasma as a source of...