Photo: Lung cancer invades a healthy cell.

Chinese scientists say that have tested a revolutionary, but controversial, gene-editing technique in a living person for the first time. Until now, the technique known as CRISPR/Cas9, had only been tested in lab animals. But this latest news reported in the journal Nature could stoke the fires already burning under US-based researchers, who want to use the gene-editing tool to treat disease.

The Chinese team, lead by oncologist Lu You at Sichuan University in Chengdu, used CRISPR/Cas9 to treat a patient with non-small-cell lung cancer as a part of a clinical trial. This could be the first step toward completely new cancer therapies.

Heralded as one of the biggest biotechnology breakthroughs of the century, the CRISPR/Cas9 technique allows scientists to repair broken genes more easily and more efficiently than previous methods. It starts with an RNA molecule that matches the DNA sequence of a targeted gene. The RNA works like a guide, bringing the enzyme Cas9 to the damaged bit of DNA, where it's used to snip out the damage, replace it or repair it.

The technique, first reported in Science in 2012 by Jennifer Doudna at the University of California, Berkeley, and Emmanuelle Charpentier, now at the Max Planck Institute for Infection Biology in Berlin, lets a researcher change any part of the DNA of any organism. It has the potential to cure diseases, engineer crops to withstand extreme environments and even eradicate pathogens.

After the Science paper was published, several scientists began experimenting with the technique. But then in 2015, scientists in Beijing used CRISPR to modify genes in a human embryo. The embryo was not allowed to develop into a human, but the implications were obvious. CRISPR could be used to modify human beings before they were born.

WATCH VIDEO: What Is CRISPR and How Could it Edit Your DNA?