Scientists have developed a single blood test that can help in the early diagnoses of eight common cancer types and helps identify the location of the disease. The test, called CancerSEEK, is a unique noninvasive, multianalyte test that simultaneously evaluates levels of eight cancer proteins and the presence of cancer gene mutations from circulating DNA in the blood. The test is aimed at screening for eight common cancer types that account for more than 60 per cent of cancer deaths in the US, researchers said. Five of the cancers covered by the test currently have no screening test. "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," said Nickolas Papadopoulos, professor of oncology and pathology at Johns Hopkins University in the US. According to the study published in the journal Science, CancerSEEK is noninvasive and can, in principle, be administered by primary care providers at the time of other routine blood work. The investigators initially explored several hundred genes and 40 protein markers, whittling the number down to segments of 16 genes and eight proteins. They point out that this molecular test is solely aimed at cancer screening and, therefore, is different from other molecular tests, which rely on analysing large numbers of cancer-driving genes to identify therapeutically actionable targets. In this study, the test had greater than 99 per cent specificity for cancer. The test was used on 812 healthy controls and produced only seven false-positive results. It was evaluated on 1,005 patients with nonmetastatic, stages I to III cancers of the ovary, liver, stomach, pancreas, esophagus, colorectum, lung or breast. The median overall sensitivity, or the ability to find cancer, was 70 per cent and ranged from a high of 98 percent for ovarian cancer to a low of 33 per cent for breast cancer. For the five cancers that have no screening tests -ovarian, liver, stomach, pancreatic and esophageal cancers -sensitivity ranged from 69 per cent to 98 per cent. "Many of the most promising cancer treatments we have today only benefit a small minority of cancer patients, and we consider them major breakthroughs," said Bert Vogelstein, professor of Oncology at Johns Hopkins University. "This test represents the next step in changing the focus of cancer research from late-stage disease to early disease, which I believe will be critical to reducing cancer deaths in the long term," said Vogelstein.