Tracking down the clues

THE Galleri test is a ‘liquid bi opsy’ developed by US-based company GRAIL.

It uses machine-learning algorithms to pick up traces of DNA shed by cancer cells.

The test looks for chemical changes, called methylation, in cell-free DNA, which can contribute to t umour growth. When cancer is detected, the test is able to i ndicate which part of the body the cancer signals are coming f rom with high accuracy.

Most of these cancers cannot be detected through current screening practices, often resulting in a poor prognosis for patients.

But, in theory, the test quickly points to a diagnosis and treatment can be started earlier, drastically improving survival chances.