The reason behind cancer being able to spread so easily may finally have been uncovered.
It turns out that tumours push through blood vessels with 200 times the force of ordinary cells, according to a study by University College London.
The study adds that this is thought to be due to cancerous cells having more receptors on their surfaces, which allow them to cluster together and act as one strong unit.
The study also highlights that blocking these receptors may help to prevent cancers spreading in the body.
The researchers created a microscopic diving-board like device to test the strength of both healthy and cancerous cells. Results showed breast cancer cells push with a force that is up to 200 times bigger than healthy cells.
Cancer cells cluster together and form a network that sticks to the walls of veins and arteries and this generates a strong force that lets tumours break through weak points in blood vessels.
Tumours are thought to be stronger due to them having more of these receptors on their surfaces and researchers believe blocking these receptors could reduce a tumour's force on blood vessel walls, which may slow or prevent cancers from spreading.
The study was published in the Nature journal Communications Biology.