People with untreatable cancers have had their immune system redesigned to attack their own tumours, BBC reported.
The experimental study involved only 16 patients, but has been called a "leap forward" and a "powerful" demonstration of the potential of such technology.
Each person had a treatment developed just for them, which targeted the specific weak spots in their tumour.
It is too early to fully assess the therapy's effectiveness and is expensive and time-consuming.
The work focuses on a part of the immune system called T-cells, which patrol the body and inspect other cells for problems.
They use proteins - called receptors - to effectively sniff out signs of infection or deviant cells that have become cancerous.
Cancers can be tricky for T-cells to spot. A virus is distinctly different to the human body, but cancers are more subtle because they are a corrupted version of our own cells.
The idea of the therapy is to boost levels of these cancer-spotting T-cells. It has to be tailored to each patient as each tumour is unique.
More about:
