Treatment modalities for melanoma Flashcards
What is cancer immunology based on?
The use of the immune system to immobilize tumours
The most important feature of the immune system
It is balanced
How do cancer cells escape immune attack?
Take advantage of the immune-regulatory mechanisms to escape immune attack
Favour immunosuppression
Describe the process of T cell activation
- TCR recognises molecules presented on APC
- Interaction leads to the progression of signal 1 which causes the T cell to become anergic
- The costimulatory signal 2 activates the T cell
What is meant when the T cells become anergic?
The cells stop to respond to the environment
Example of a costimulatory signal 2
CD28 on T cells bind to CD80/86 on APCs
Signal 1 is enough to induce activation of the T cell
TRUE or FALSE
FALSE
Full response by T cell is stimulated once both signal 1 and 2 are transduced in the T cell
What is immunosurveillance?
Process that happens as the cells transition form the normal to transformed physiology.
Immune cells go into the tumour and, if the tumour is immunogenic it will be destroyed by the immune system by elimination
What is equilibrium?
Process that leads to established tumour masses.
Some tumour cells survive process of elimination
Some regulatory processes shut down the T cell response (regulatory cells, CTLA-4, immunomodulatory receptors)
Leads to equilibrium in the tumour microenvironment
Many tumour cells remain in equilibrium
TRUE or FALSE
FALSE
In most cases, tumour cells are able to escape equilibrium due to anti-inflammatory cytokines and mutations
Leads to formation of established tumours
What is CTLA-4?
Cell surface marker
What is the importance of CTLA-4 in cancer pathogenesis?
Prevents T cells from binding to the cancer cells
How does CTLA-4 prevent T cells from binding to cancer cells?
Blocks CD28 from interacting with CD80/86 in APCs
What is another master regulator in the immune response?
PD-1
How is PD-1 involved in tumour progression?
PD-L1 immunosuppressant protein found on the surface of tumour cells
Bind to PD-1 on T cells
Suppresses T cells
What happens to cancer cells without PD-L1?
T cells degranulate and release their cell contents
Stimulates an immune response
What are cancer therapies targetting PD-L1 and CTLA-4 designed to do?
Block these transmembrane proteins
Allowing the T cells to kill the cancer cells
What is the best therapy regarding anti-PD-L1 and CTLA-4 remedies?
Combination therapy
What is the potential harm of cancer immunotherapies?
Disrupts the fine balance of the immune system
Can favour autoimmunity
What is a potential treatment for cancer?
Sequencing of cancer cells
Identifying mutations that are likely to be recognised by the immune system
Form vaccines expressing the mutations
Train the immune system to recognise antigen sequences on the cells
What are markers of regulatory T cells?
CD4
Foxp3
What are markers of cytotoxic T cells?
CD8
