Blood Test Could Spot Multiple Cancer Types, Researchers Say
WEDNESDAY, May 29, 2019 (HealthDay News) -- A gene-based blood test can accurately detect breast, colorectal, lung, ovarian, pancreatic, gastric or bile duct cancers in patients, researchers report.
The test uses artificial intelligence to identify and interpret "fragments" of DNA in the blood that indicate the presence of cancer, explained researchers led by Dr. Victor Velculescu. He helps direct the Cancer Biology Program at the Johns Hopkins Kimmel Cancer Center in Baltimore.
In the new study, the test -- called DELFI (DNA evaluation of fragments for early interception) -- accurately detected cancer in 73% of cancer patients overall, and only misclassified four out of 215 patients, meaning it had just a 2% error rate.
"DELFI helps identify the presence of cancer by detecting abnormalities in the size and amount of DNA in different regions of the genome based on how it is packaged," said lead author Jillian Phallen, a postdoctoral fellow at the Kimmel Cancer Center.
Still, this is just a proof-of-concept study, the researchers said, and more research is needed before it reaches routine use.
But such "liquid biopsies" are a holy grail of cancer research, potentially making cancer diagnosis easier and faster, and avoiding the need for invasive tissue biopsies.
Many blood-based biopsies are under development, but DELFI relies on a slightly different strategy than most. According to the Hopkins team, the test examines the way DNA is packaged within the cell nucleus. While healthy cells package their DNA in ordered, predictable ways, cancer cells do not -- instead, DNA appears more disordered and random.
This "means that when cancer cells die they release their DNA in a chaotic manner into the bloodstream," Phallen explained in a Hopkins news release. And it's these disorganized bits of DNA that the new test detects.
In the new trial, involving 208 cancer patients, DELFI accurately spotted one of seven cancers between 57% and 99% of the time in blood samples, the team reported May 29 in the journal Nature.
The study group included 54 breast cancer patients, 27 colorectal cancer patients, 12 lung cancer patients, 28 ovarian cancer patients, 34 pancreatic cancer patients, 27 gastric cancer patients and 26 bile duct cancer patients.
Genomic testing from these patients was compared to results from a comparison group of 215 healthy individuals.
As expected, the DNA fragmentation "profiles" of the healthy individuals were more ordered and much less variable than those of the cancer patients.
Besides simply spotting the presence of a cancer, the new blood test was between 61% and 75% accurate in determining the tissue of origin of the tumor, the study authors reported.
And when data from DELFI was added to another mutation-based analysis of "cell-free" DNA, this analysis accurately spotted tumors in 91% of the cancer patients, the investigators found.
This research remains in its early stage. However, "we're encouraged about the potential of DELFI because it looks at a completely independent set of cell-free DNA characteristics from those that have posed difficulties over the years," Velculescu said. "We look forward to working with our collaborators worldwide to make this test available to patients."
The researchers added that because the blood test is easy to administer and analyze in the lab, it could also prove to be a cost-saver.
For current guidelines on cancer screening, head to the American Cancer Society.
SOURCE: Johns Hopkins Kimmel Cancer Center, news release, May 29, 2019