Skip to 0 minutes and 14 seconds SPEAKER 1: So assuming the immune system does play a role in combating cancer, how then do tumour cells avoid being attacked?
Skip to 0 minutes and 23 seconds Firstly, whereas infected cells can look quite different to the immune system from normal cells, often the changes in cancer cells are quite subtle so they can look pretty similar to the immune system. This means that in many cases they are inherently disguised. Despite this, by inspecting target cells closely, immune cells can potentially recognise and destroy cancer cells. However, cancer cells have a number of tactics they use to evade an immune cell poised to attack. Here, we will show you three tricks. Firstly, cancer of cells can send direct messages in the form of small proteins called cytokines that tell the immune cells to ignore the cancer cell.
Skip to 1 minute and 5 seconds Secondly, as we’ve heard, T cells rely on special cellular MHC molecules that display bits of proteins that are located inside the cancer cell for recognition. If tumour cells lose these systems of surveillance, it effectively means they can escape close inspection. Thirdly, cancer cells can exploit the fact that our immune cells have emergency off switches on their surface to prevent them going out of control. By pressing these off switches, cancer cells can turn off our immune cells when they are poised to attack. Finally, it’s useful to think about cancer as evolving like in Darwinian evolution. Cancer cells can mutate and change over time, creating a diverse population of cells.
Skip to 1 minute and 49 seconds The cancer cells that’s are most adept at survival and about suppressing the immune system are the most likely to come to dominate the population. Understanding how this occurs is crucial if we are to develop novel approaches to cancer treatment.
Survival of the sneakiest: how tumours escape immune attack
We know that the immune system is extremely efficient at responding to foreign invaders. In the last few tasks we have been looking at evidence that the immune system can also attack cancer cells. So if this is the case, why is it such a challenge for the immune system to eliminate cancer?
Your task: watch the video animation explaining some of the mechanisms cancer cells use to avoid the immune system. Reflect on any new information or ideas and share your thoughts with other learners in the comments area.
© Cancer Immunology and Immunotherapy Centre, University of Birmingham