“I think we are really living a revolution” said Dr Nadia Guerra, head of Imperial’s Inflammation and Tumour Immunity lab. The revolution in question is happening within cancer medicine, the charge led by its latest weapon: immunotherapy.
The idea of the immune system being able to fight cancer might sound like wishful thinking, but that is precisely the principle underpinning immunotherapy. What happens normally in cancer patients is that diseased cells in and around the tumour are blocked from being destroyed. ‘Checkpoint blockade’ immunotherapy removes this block, allowing the immune cells to deliver their lethal hit. This type of treatment has already delivered impressive results in patients with advanced skin cancer, famously including ex-US president Jimmy Carter whose cancer had spread to his brain but is now ‘cancer free’.
“It’s very exciting” said Dr Guerra. “Clearly, surgery is the way to go whenever it’s possible, but now there is a lot of discussion about how we combine immunotherapy with chemotherapy or radiotherapy. Which one should come first?”
However, immunotherapy does not work in everyone, so researchers are looking for ways to improve its success rate. Cancer cells have various specific molecules on their surface which help to identify them as dangerous. To detect them, some immune cells have receptors which specifically attach to these molecules. An approach called core T-cell therapy involves a patients’ own immune cells being engineered in the lab to display these receptors, making it easier for their immune system to recognise and attack tumour cells.
One of these receptors, called NKG2D, has been studied in mice by Dr Guerra and her team. This receptor binds specifically to a molecule found on several types of tumour. She has already shown that in some cancers, NKG2D seems to help slow down tumour growth, making it an ideal candidate for use in immunotherapy. However, her most recent study found that it can also have the opposite effect in cancers linked to inflammation, such as liver cancer, possibly because NKG2D can also bind to inflamed non-cancerous cells with the same molecule on their surface. Clearly, this has implications for its application in cancer treatment. Guerra says we need to understand more about the immune system, but also about tumour biology. This way, we can ensure treatments are given to patients they will actually work on.
Despite this, immunotherapy is definitely having a moment. For Guerra, it is real: “Finally, after years and years of questioning the importance of the immune system in rejecting tumours, it is proving that the immune system is relevant, and its most likely what keeps us tumour free.”
Helena Spooner is studying for an MSc in Science Communication at Imperial College London
Banner image: immunotherapy research concept, CI Photos