A simple blood test could detect breast cancer up to five years before any clinical signs of the disease, according to research.
Researchers are developing the test which they say identifies the body’s immune response to substances produced by tumour cells.
Cancer cells produce proteins called antigens that trigger the body to make antibodies against them – autoantibodies.
Researchers at the University of Nottingham have found these tumour-associated antigens (TAAs) are good indicators of cancer.
They have developed panels of TAAs that are associated with breast cancer to detect whether there are autoantibodies against them in blood samples taken from patients.
Autoantibodies against a number of TAAs can be detected up to five years before clinical signs of the tumour.
In a pilot study the scientists, part of the Centre of Excellence for Autoimmunity in Cancer (CEAC) group at the School of Medicine, University of Nottingham, took blood samples from 90 breast cancer patients at the time they were diagnosed.
They matched them with samples taken from a control group of 90 patients without breast cancer.
Details of the experimental study conducted in people and cells were presented at the National Cancer Research Institute (NCRI) conference in Glasgow.
Daniyah Alfattani, a PhD student in the research group, said: “The results of our study showed that breast cancer does induce autoantibodies against panels of specific tumour-associated antigens.
“We were able to detect cancer with reasonable accuracy by identifying these autoantibodies in the blood.”
Researchers identified three panels of TAAs against which to test for autoantibodies.
According to the research, the panel of five TAAs correctly detected breast cancer in 29% of the samples from the cancer patients and correctly identified 84% of the control samples as being cancer-free.
The panel of seven TAAs correctly identified cancer in 35% of cancer samples and no cancer in 79% of control samples.
The panel of nine antigens correctly identified cancer in 37% of cancer samples and no cancer in 79% of the controls.
Ms Alfattani added: “We need to develop and further validate this test. However, these results are encouraging and indicate that it’s possible to detect a signal for early breast cancer.
“Once we have improved the accuracy of the test, then it opens the possibility of using a simple blood test to improve early detection of the disease.”
Now the scientists are testing samples from 800 patients against a panel of nine TAAs.
They estimate that, with a fully funded development programme, the test might become available in the clinic in about four to five years.
A similar test for lung cancer is being tested in a randomised controlled trial in Scotland, involving 12,000 people at high risk of developing lung cancer because they smoke.
However experts have warned that the research is in the early stages, and highlight that samples from breast cancer patients from five years before they were diagnosed have not been tested.
Paul Pharoah, professor of cancer epidemiology, University of Cambridge, said: “These are clearly very preliminary data and a lot more research would be needed before any claim can be made that this is likely to represent a meaningful advance in the early detection of cancer.
“I think it is too soon to even claim that the research is promising.”
Lawrence Young, professor of molecular oncology at the University of Warwick, said: “While this is encouraging research, it is too soon to claim this test could be used to screen for early breast cancer.
“More work is needed to increase the efficiency and sensitivity of cancer detection.”