Immunotherapy for Cancer

Question 1

How are cancer cells different from normal cells?

Answer 1

Cancer cells:
have rapid uncontrolled growth
more mobile, which allows them to reach and invade tissue
Invade tissue
Evade immune system 
Metastasize

Question 2

What does Tumour Immunosurveillance mean?

Answer 2

‘Immunosurveillance’ coined by Burnet & Thomas in 1957 to describe a process where the immune system, namely lymphocytes, continually recognise cancerous and pre-cancerous cells leading to their elimination before they can cause damage.
But Tumours do develop highlighting the fact that Immunosurveillance is not perfect.

Question 3

What term replaces Immunosurveillance now?

Answer 3

Immunoediting

Better explanation, divided into 3 phases  
                              (3 Es)
Elimination.
Equilibrium.
Escape.

Question 4

Describe the 3 phases of Immunoediting

Answer 4

1.Elimination:
involved are NKs, NKTs, Macs and DCs (Innate).
INFγ and chemokines lead to tumour death.
Tumour specific DCs activate adaptive immunity in draining lymph nodes.
Tumour specific CD4+ and CD8+ T cells join.

2.Equilibrium
Elimination phase is incomplete.
Tumour cells lie dormant and may modulate tumour antigen expression and stress signals.
The immune system eliminates susceptible tumour clones when possible sufficient to prevent tumour expansion.
Tumour heterogeniety resulting in ‘Darwinian selection’

3. Escape (tumours can escape the immune system)
   Immune system is unable to control the tumour growth leading to tumour progression.