Blood test for eight types of cancer offers promising early results
A new blood test designed to detect eight common types of cancer is showing excitingly positive results in early trials. Developed by a team led by researchers at Johns Hopkins Kimmel Cancer Center, the test tracks two different types of biomarkers that can signal the presence of the disease.
Research into developing a simple blood test that can detect cancer is moving slowly but surely despite the inherent difficulties in the technique. Finding specific biomarkers that conclusively indicate the presence of cancer is proving challenging, but several recent breakthroughs have offered scientists new hope.
Researchers at Purdue University last year revealed a promising study focusing on a series of proteins that could effectively signpost the presence of cancer, while a Johns Hopkins team successfully developed a method that can identify mutated DNA in a blood sample as a marker of early-stage cancer.
This new test, called CancerSEEK, blends the two techniques to screen for cancers of the ovary, liver, stomach, pancreas, esophagus, colorectum, lung, and breast. Five of these cancers covered by the test currently have no commonly used screening method.
"The use of a combination of selected biomarkers for early detection has the potential to change the way we screen for cancer, and it is based on the same rationale for using combinations of drugs to treat cancers," explains senior author on the new study, Nickolas Papadopoulos.
The test is composed of a detection panel that focuses on eight proteins and 16 gene segments. Specificity in targeting was important as false-positives can cause unnecessary hardship on patients. In the recently published study the test returned only seven false-positive results when used on 812 healthy control subjects. This equates to a 99 percent specificity rate.
The test was also trialed on 1,005 patients with diagnosed cancers at various nonmetastatic stages. On average, the test was found to be 70 percent successful but some cancers were more effectively picked up than others. Breast cancer was the least positively identified with a success rate of only 33 percent, but ovarian cancer was extraordinarily well identified, with a 98 percent rate of success.
Broad application of the test is still some years away but the research team is currently embarking upon a large-scale study that will involve over 10,000 healthy subjects. As with other prospective cancer blood tests, questions still remain over how specific these biomarkers are to the cancers they are designed to identify and whether other non-cancerous factors can affect the levels of the proteins examined.
The study was published in the journal Science.