Immunotherapy in cancer is at present the most promising cancer management therapeutic due its ability to coordinate the body’s own immune system, training it to recognise and target cancer cells. This will reduce cancer from progressing to the stage where it spreads and becomes fatal, it will also work to minimise tumours and prevent cancers from recurring. So how does this actually work?
The aim of immunotherapy is to perpetuate the cancer immunity cycle. The cycle works by the release of cancer cell antigens (CCAs) upon cancer cell death, allowing the body’s immune system to recognise these CCAs and priming our T-cells (a type of immune cell) to recognise and bind to the site of the cancer, to ultimately kill it.
…FYI, antigens are proteins which can induce an immune response, now you see why this is called immunotherapy, it’s stimulating our immune system!
Immunotherapy works by using what we call monoclonal antibodies which target an antigen. Antibodies are proteins which recognise other proteins that they can match with either foreign antigens on bacteria/viruses, or the body’s own cell antigens.
Think of it as lock and a key, antibodies will only find one antigen that they’ll bind to, and a key will only open one lock that it fits in. Monoclonal is referring to the fact that there are many clones of one antibody.
As the video explains, cancer cells mask themselves and mimic healthy cells and hence evade the immune system through their PD-1 and PD-L1 interaction. It’s almost like they’re connecting to each other to make sure they’re still allies, but as soon as the connection is interrupted, the immune cells view the cancer cells as enemies and go on to attack.
Once the cancer cells have died, their antigens are released, open for the immune cells to recognise and class as foreign, so when they come into contact with the same antigen again they eradicate it, hence perpetuating the cancer immune cycle.
On the other hand, immunotherapy lacks as an effective treatment due to its age-related efficacy, a lot of studies around it have been based on younger patients, despite the treatment working with older patients, it’s still not as effective.
So here we have one limitation to immunotherapy – understanding the changes in specific tumours in different ages will help contribute towards making a treatment with higher efficacy. The reduced efficacy may be due to an aged immune system not being as strong as a younger one, lacking in the important cells needed to create an immune response, such as T-cells.
Perhaps another improvement that could be made on immunotherapy is that like the vaccines mentioned in previous blogs, we can use a combination immunotherapy to heighten the immune response to the unmasked cancer cells.
Immunotherapy is still very new, exciting and inspiring… but it still has a long way to go. We can only dream of a day when there comes a cure to cure all cancer.