A new blood test to detect eight types of cancer shows promise, researchers say. The experimental test, called CancerSEEK, has been developed by a team at Johns Hopkins University. It focuses on detecting eight major cancers: lung, breast, colon, pancreas, liver, stomach, ovary and esophagus. The test looks for genetic mutations in genes and proteins that are typically linked with those cancers.
The researchers studied 1,005 people who had been diagnosed with those cancers. The blood test found signs of cancer in about 70 percent of them.
The test first looks for 16 genetic mutations found in bits of DNA that have been shed by cancerous cells. It also screens for eight proteins that are often found in increased amounts in people who have cancer.
Researchers are now doing trials with people who haven't been diagnosed with cancer. That will be the true test of its effectiveness. Then the goal will be to make the test affordable so that it can be given annually. That way people can be screened regularly and cancer can be caught early when it is most treatable.
"The goal is to look for as many cancer types as possible in one test, and to identify cancer as early as possible," lead researcher Nickolas Papadopoulos, a professor of oncology and pathology at Johns Hopkins, told the Los Angeles Times. “We know from the data that when you find cancer early, it is easier to kill it by surgery or chemotherapy.”
Papadopoulos told NPR that the research team hopes to make each test cost about $500, but ultimately whatever company licenses the patent from Johns Hopkins will set the price.
The study results were published in the journal Science.
Other tests in the works
This isn't the first test researchers have been developing to detect cancer.
Still in its early stages, another blood test for the early detection of cancer also has delivered promising results, say researchers.
The test also searches blood samples for small bits of DNA, deposited by dying cancer cells into the bloodstream. In the study of 124 patients with advanced cancers, the test was able to detect at least one genetic change in 89 percent of the people who were studied.
The study results were presented at the June 2017 American Society of Clinical Oncology (ASCO) Annual Meeting.
The test has been referred to as a "liquid biopsy," but it differs from those tests, which only study a small part of the genetic material of already-diagnosed patients. The goal in that case it to monitor the disease for treatment.
In this case, the test scans a broad area of the genome, resulting in about 100 times more data than other sequencing approaches, according to the researchers. The test scans blood samples for mutations in 508 genes, with each region of the genome sequenced or "read" 60,000 times.
And although in this early stage, the test scanned blood samples for DNA in people already diagnosed with cancer, the researchers hope to develop a test for people who have no symptoms and have not been diagnosed with the disease.
"Our findings show that high-intensity circulating tumor DNA sequencing is possible and may provide invaluable information for clinical decision-making, potentially without any need for tumor tissue samples," lead study author Dr. Pedram Razavi of Memorial Sloan Kettering Cancer Center, said in a statement. "This study is also an important step in the process of developing blood tests for early detection of cancer."
“We continue to see promising reports about possible uses of circulating tumor DNA analysis," said American Society of Clinical Oncology's John Heymach, M.D, Ph.D. "While this approach has a ways to go before it becomes a proven technology for early cancer detection, this research is an important step in that direction.”
Editor's note: This story has been updated since it was published in June 2017.