Cancer cells excel at evading detection, but subtle chemical differences set them apart from healthy cells. Now, a team of scientists from Wageningen University & Research and Van Andel Institute has identified a way to exploit this distinction. Using a variant of CRISPR, a modern tool for editing DNA, they distinguished tumor DNA from healthy DNA and selectively cut only the former. The study, published today in Nature, is an early but promising step toward a cancer therapy that targets and destroys tumor cells with high precision.

The new method relies on methyl groups, small chemical tags attached to DNA that regulate whether genes are on or off. This process, called DNA methylation, is altered in cancer cells and can act as a molecular “fingerprint” that differentiates malignant cells from healthy ones.