It may explain why some patients do not respond well to immunotherapy drugs that destroy tumors.

Taking glucocorticoids (GCs) fuels a protein linked to poorer outcomes, scientists say.

“GCs are very powerful suppressors of immunity and are consequently used to treat autoimmunity, which is when the immune system attacks healthy cells.

“We have previously shown that GCs can also break cancer immunotherapy. Now, here is perhaps a clue into how they are doing it.”

Asthma, arthritis and eczema patients are all routinely prescribed steroids.

Immunotherapy uses the body’s own immune system to recognize cancer cells – and kill them.

It can be administered as tablets, injections or inhaled. But patients sometimes experience side effects GKs can treat.

But they also produce a protein called CyC (Cystatin C), higher levels of which interfere with immunotherapy.

Cancer patients who were more likely to produce CyC in response to GCs had a worse overall survival rate.

These patients were also less likely to benefit from treatment – suggesting CyC production within a tumor may contribute to the failure of immunotherapy.

The discovery was confirmed by experiments in mice. When a CyC-producing gene was deleted so it was no longer present in tumors, they grew slower.

“Clever genetic models gave us some indication of which experiments to design to help us answer the question of what this molecule does.”

“Perhaps its function can be targeted to enhance the success of cancer immunotherapy.”

Produced in association with SWNS Talker

Edited by Asad Ali and Saba Fatima