How a healthy immune system protects against cancer
Why do cancers occur?
Our bodies' cells are continually dividing and making copies. However, the fast rate at which cells grow and divide results in errors and these cells become damaged abnormal cells.
Up to 10,000 mistakes occur in the DNA of dividing cells in our body every day, making cancer cells formation not only common but inevitable. Unfortunately, with increasing age, there are more damaged cells.
What role does your immune system play?
Our immune system recognises and destroys these microscopic cancer cells all the time. A group of immune cells, called NK cells or killer T cells, are the ones primarily responsible for patrolling your body and destroying damaged cells or small tumours before they cause us harm.
There are two phases in your immune system's defence:
1. Eliminating phase
Our immune system does an excellent job of killing these individual cancer cells as they occur in the very early stage. The immune cells are in control and can easily cope with the task.
2. Equilibrium phase
When the growth rate of the tumour equals the immune system activity, this is the equilibrium phase. The immune system is still able to cope even though the workload is increasing.
The main reason that microscopic cancers don't grow is that our body's defence deprives these cancer cells of a blood supply. As long as there is no blood supply and nutrients to feed these tumours, the cancer cells are starved and remain dormant and harmless.
How do these cells develop into full-blown cancer?
As time goes on, cancer cells can start to change and grow. They find ingenious ways to escape detection of the immune surveillance system. They wrap themselves in 'friendly' proteins that fool the immune system into recognising them as normal cells. This subterfuge effectively makes them invisible to escape detection.
Other times, the immune system is weakened and unable to do its job adequately, so cancer cells are missed and can grow. And as we age, our cells get worn down and do not work as well as before.
When the immune system is overwhelmed, tiny nests of cancer cells can release factors that stimulate blood vessels sprouting in the cancer cells. With this nourishment of a blood supply, cancer grows exponentially and becomes full-scale cancer. Conversely, without this excessive blood supply, cancer is inhibited from growing and spreading.
Immunotherapy uses the immune system to eliminate cancer cells
One type of immunotherapy cancer treatment works by blocking the proteins that cancer uses to hide from the immune system. These drugs are called Checkpoint Inhibitors. Once the cancer cells become visible to the immune system, the immune army arrives to destroy them.
Another exciting advancement in cancer treatment is CAR-T therapy, approved in the USA for leukaemia and lymphoma. It also appears to be effective for colon cancer. This procedure involves collecting blood from the patient, removing the immune T-cells, and returning the blood to the patient. The T cells are genetically engineered to become CAR-T cells. This approach gives the T cells extra resources to recognise the proteins on the cancer cells, target and eradicate the cancer cells.
The upshot is that our immune system is critical in protecting us against cancer and other illnesses.
Take care of your immune system every day.