Researchers from Johns Hopkins Medical Center are reporting in the journal Science that they have come up with a new a blood test that can detect eight common cancer types by assessing the levels of circulating proteins and DNA mutations. Five of the cancers covered by the test currently have no available screening test.
Called CancerSEEK, this test is a multianalyte test that simultaneously evaluates levels of eight cancer proteins and the presence of cancer gene mutations from circulating DNA in the blood. “The goal was always a single blood test for all eight cancers, but it could be extended to other cancers. The principles behind this test can be applied to any cancer,” said the paper’s first author Joshua Cohen, MD, who is a researcher at the Ludwig Center for Cancer Genetics and Therapeutics at Johns Hopkins University School of Medicine in Baltimore, Maryland.
The investigators initially explored several hundred genes and 40 protein markers and narrowed the number down to segments of 16 genes and eight proteins. Cristian Tomasetti, PhD, who is an associate professor of oncology and biostatistics at Johns Hopkins, helped develop the algorithm and said this approach employed machine learning to enable the test to accurately determine the location of a tumor down to a small number of anatomic sites in 83% of patients. To zero in on the analytes, the investigators pulled data from more than three decades of cancer genetics research generated at Johns Hopkins.
In this study, the test had greater than 99% specificity for cancer. When evaluated in 812 healthy controls, the test produced only seven false-positive results. The study also included 1,005 patients with nonmetastatic, stage I to III cancers of the ovary, liver, stomach, pancreas, esophagus, colorectum, lung, or breast. The median overall sensitivity was 70% and ranged from a high of 98% for ovarian cancer to a low of 33% for breast cancer. For the five cancers that have no screening tests (ovarian, liver, stomach, pancreatic and esophageal cancers), sensitivity ranged from 69% to 98%.
“I think what is significaant about this study is that it is a crucial first step. There is a lot of more important work to be done,” Dr. Cohen told Cancer Network. “We don’t want to overpromise anything and it is important to validate in studies to make sure it translates into a real survival benefit.”
The eight common cancer types involved in the test account for more than 60% of cancer deaths in the United States. It is envisioned that this test will be administered by primary care providers at the time of other routine blood work. “The hope is it will cost $500 or less. It will have to be affordable, comparable to mammography or colonoscopy,” said Dr. Cohen.