Written by Hannah Devlin Science correspondent
DNA and biomarkers could be used to detect and identify cancers, including five types for which there is currently no screening test.
Scientists have made a major advance towards developing a blood test for cancer that could identify tumours long before a person becomes aware of symptoms.
The new test, which is sensitive to both mutated DNA that floats freely in the blood and cancer-related proteins, gave a positive result approximately 70% of the time across eight of the most common cancers when tested in more than 1,000 patients.
In the future, such a test could be used in routine screening programmes to significantly increase the proportion of patients who get treatment early, at a time before cancer would typically show up on conventional scans.
“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 at Johns Hopkins University and senior author on the paper.
The test could also identify the form of cancer that a patient had, a goal that previous cancer blood tests have failed to achieve.
It works by detecting free-floating mutated DNA, released into the bloodstream by dying cancer cells. The test screened for the presence of errors in 16 genes that are frequently mutated in different kinds of cancer. The blood of patients was also tested for eight known protein biomarkers which are seen to differing degrees depending on where in the body a tumour is located.
In blood samples from 1,005 patients, the test detected between 33% and 98% of cases of disease. Ovarian cancer was the easiest to detect, followed by liver, stomach, pancreas, oesophageal, colorectal, lung and breast cancers.
For the five cancers that currently have no screening tests – ovarian, liver, stomach, pancreatic and oesophageal cancers – sensitivity ranged from 69% to 98%.
For more read the full of article at The Guardian
