This blood test can detect breast cancer even before clinical signs: Study

Researchers have found that a simple blood test can detect breast cancer up to five years before there are any clinical signs of it.

The blood test identifies the body's immune response to substances produced by tumour cells, according to the research presented at the 2019 NCRI (National Cancer Research Institute) Cancer Conference in Glasgow, UK, on Sunday.

"We need to develop and further validate this test," said Daniyah Alfattani from University of Nottingham in Britain.

"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," she said.

Cancer cells produce proteins called antigens that trigger the body to make antibodies against them -- auto-antibodies.

The researchers have found that these tumour-associated antigens (TAAs) are good indicators of cancer, and now they have developed panels of tumour-associated antigens that are known already to be associated with breast cancer to detect whether or not there are auto-antibodies against them in blood samples taken from patients.

In a pilot study, the researchers took blood samples from 90 breast cancer patients at the time they were diagnosed with breast cancer and matched them with samples taken from 90 patients without breast cancer (the control group).

They used screening technology (protein microarray) that allowed them to screen the blood samples rapidly for the presence of auto-antibodies against 40 tumour-associated antigens associated with breast cancer, and also 27 tumour-associated antigens that were not known to be linked with the disease.

"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 auto-antibodies in the blood," Alfattani said while presenting the research.

The researchers identified three panels of tumour-associated antigens against which to test for autoantibodies. The accuracy of the test improved in the panels that contained more tumour-associated antigens.

The panel of five tumour-associated antigens correctly detected breast cancer in 29 per cent of the samples from the cancer patients and correctly identified 84 per cent of the control samples as being cancer-free.

The panel of seven tumour-associated antigens correctly identified cancer in 35 per cent of cancer samples and no cancer in 79 per cent of control samples. The panel of nine antigens correctly identified cancer in 37 per cent of cancer samples and no cancer in 79 per cent of the controls.

The researchers are now testing samples from 800 patients against a panel of nine tumour-associated antigens, and they expect the accuracy of the test to improve with these larger numbers.

"A blood test for early breast cancer detection would be cost effective, which would be of particular value in low and middle income countries. It would also be an easier screening method to implement compared to current methods, such as mammography," said Alfattani.