Brain tumours fly under the radar of the body's defence forces by coating their cells with extra amounts of a specific protein, according to a new research.
The findings, made in mice and rats, show the key role of a protein called galectin-1 in some of the most dangerous brain tumours, called high grade malignant gliomas.
A research team from the University of Michigan Medical School uncovered galectin-1's role by pursuing a chance finding.
They had been trying to study how the extra production of galectin-1 by tumour cells affects cancer's ability to grow and spread in the brain.
Instead, they found that when they blocked cancer cells from making galectin-1, the tumours were eradicated; they did not grow at all.
That's because the "first responders" of the body's immune system - called natural killer or NK cells - spotted the tumour cells almost immediately and killed them.
But when the tumour cells made their usual amounts of galectin-1, the immune cells couldn't recognise the cancerous cells as dangerous.
That meant that the immune system couldn't trigger the body's "second line of defence", called T cells - until the tumours had grown too large for the body to beat.
Team leader Pedro Lowenstein, of the U-M Department of Neurosurgery, said the findings open the door to research on the effect of blocking galectin-1 in patients with gliomas.
The study was published in the journal Cancer Research.
