A new blood test in development from GRAIL, Inc. and studied by investigators at the Dana-Farber Cancer Institute has the ability to accurately screen for numerous types of cancer.
Data from the study was presented at the European Society for Medical
Oncology (ESMO) 2019 Congress. The study showed that the
next-generation sequencing technology can probe DNA for chemical tags
known as methylation that influence whether genes are active or
inactive, Dana-Farber said this morning. According to the study, the
technology probed 3,600 blood samples, some from patients with cancer
and some from those who had not been diagnosed, and the test was able to
pick up on cancer signals. Additionally. The test correctly identified
the tissue from where the cancer began. Dana-Farber said the test’s
specificity was high, as was its ability to pinpoint the organ or tissue
of origin, researchers found.
GRAIL’s test looks for DNA, which cancer cells shed into the
bloodstream when they die. In contrast to “liquid biopsies,” which
detect genetic mutations or other cancer-related alterations in DNA, the
technology focuses on modifications to DNA known as methyl groups,
Dana-Farber said. Methyl groups are chemical units that can be attached
to DNA, in a process called methylation, to control which genes are “on”
and which are “off.” Abnormal patterns of methylation turn out to be,
in many cases, more indicative of cancer — and cancer type — than
mutations are. The test zeroes in on portions of the genome where
abnormal methylation patterns are found in cancer cells, Dana-Farber
noted in its announcement.
Dana-Farber’s
study showed that the GRAIL test had a specificity of 99.4%, meaning
only 0.6% of the results incorrectly indicated that cancer was present.
The sensitivity of the assay for detecting a pre-specified high
mortality cancers was 76%. Within this group, the sensitivity was 32%
for patients with stage I cancer; 76% for those with stage II; 85% for
stage III; and 93% for stage IV. Sensitivity across all cancer types was
55%, with similar increases in detection by stage. For the 97% of
samples that returned a tissue of origin result, the test correctly
identified the organ or tissue of origin in 89% of cases, Dana-Farber
said in its announcement.
Dana-Farber’s Geoffrey Oxnard and lead author of the study said
previous work indicated that methylation-based assays outperform
traditional DNA-sequencing approaches to detecting multiple forms of
cancer in blood samples.
“The results of the new study demonstrate that such assays are a
feasible way of screening people for cancer,” Oxnard said in a
statement. He added that the results of this study indicate that if the
test were in wide use, it could help patients receive more effective
treatments.
Data presented by GRAIL in the spring at the 2019 American Society of
Clinical Oncology showed GRAIL’s investigational multi-cancer blood
test detected a strong signal for 12 deadly cancer types at early stages
with a very high specificity of at least 99%.
The test was aimed at 12 pre-specified cancer types, including
anorectal, colorectal, esophageal, gastric, head and neck, hormone
receptor-negative breast, liver, lung, ovarian, and pancreatic cancers,
as well as multiple myeloma and lymphoid neoplasms. These types of
cancer make up about 63% of cancer deaths in the United States, the
company said. The combined analysis of this group of cancers showed
robust detection at early stages, 34%, 77%, and 84% at stages I, II, and
III, respectively, GRAIL noted at the time it presented its own data.
https://www.biospace.com/article/blood-test-can-accurately-screen-for-cancers-dana-farber-study-shows/
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