Hello Nature readers,
This week, we learn that tumour cells can confuse the immune system by overstimulating the STING pathway, discover how γδ T cells find and destroy a wide range of cancers and hear that a tiny device inserted mid-surgery might help oncologists to personalize treatment for brain cancer.

Cancer's STING operation

Tumour cells trick the immune system into complacency by persistently activating the stimulator of interferon genes (STING) pathway. This pathway normally alerts the body to foreign or damaged cells, but it becomes desensitized when overstimulated. Researchers tracked interactions between cells using a new computational method called ContactTracing. Chronic activation of the STING pathway led to the rewiring of downstream signalling, stifling the immune response and allowing cancer cells to spread. The finding might explain why drugs that stimulate this pathway have so far failed as cancer treatments.

How γδ T cells get their super powers

Researchers have discovered what triggers immune cells called gamma delta (γδ) T cells to fight a broad range of cancers. Using a CRISPR screen to tweak thousands of genes, the team found that, when a cancer cell is under stress, the number of butyrophilins on its surface increases. Butyrophilins are part of a protein complex that γδ T cells recognize, triggering them to kill the cancer. If cancer cells can be manipulated to overexpress butyrophilins, this could improve the performance of γδ T cells. People with more γδ T cells tend to have better cancer outcomes.

Microdevices test nine drugs inside gliomas

Inserting tiny devices into brain tumours for a few hours during surgery might help oncologists to determine which chemotherapy will be most effective for each patient. In a proof-of-concept study, microdevices smaller than the tip of a pen were implanted into the brain tumours of six adults for up to 3 hours during surgery. The devices released nine chemotherapies into different parts of the tumours. After surgery, the response of cancer cells to each chemotherapy was analysed, revealing that some drugs were more effective than others at damaging and killing the tumours, and that each patient had a different response to each chemotherapy.

Possible immunotherapy for ovarian cancer

A protein called interferon-ε could be the first effective immunotherapy for ovarian cancer. Experiments using tumour-cell lines and mice revealed that this cytokine is expressed in the fallopian tube, where some types of ovarian cancer originate, and that tumours occur when the protein is absent.

T cells with six base edits melt solid tumours

Solid tumours in eight mice disappeared after treatment with chimeric antigen receptor (CAR) T cells that had been base edited six times. Base editing creates a single alteration in the genetic code. Three of these base edits allowed the T cells to survive transfer from a donor to a recipient; the other three helped the immune cells to fight solid tumours. Alyssa, a teenage girl with leukaemia, was successfully treated last year with CAR T cells that had been base-edited four times. "Six, I think, is the most that we've ever seen," says molecular biologist and co-author Ryan Murray.