cancer

Question 1

what is the cancer immunity cycle

Answer 1

a series of events that must take place for an effective immune response to fight cancer cells

Question 2

what do the steps describe

Answer 2

how the immune system balances the recognution of, and defense aginst, non-self molecule and the prevention of autoimmunity

Question 3

what are the steps called of the cancer immunity cycle

Answer 3

1. release of cancer cell antigens (cancer cell death)
2. cancer antigen presenation (dendritic cells/APCs)
3. priming and activation (APCs and T-cells)
4. trafficking of T-cells to tumours (CTLs)
5. infiltration of T-cell into tumours (CTLs, endotherlial cells)
6. recognition of cancer cells by t-cells
7. killing of cancer cells (immune and cancer)

Question 4

Release of cancer cell antigens (cancer cell death)

Answer 4

Antigens are released by mutated cancer cells, indicating that they are not healthy cells. The immune
system is able to recognize these antigens.

Question 5

cancer antigen presentation (dendritic cells/A P C s)

Answer 5

The cells of the immune system capture the released antigens and travel to the lymph nodes where
they find T-cells.

Question 6

Priming and activation (A P C s & T-cells)

Answer 6

T-cells are activated by the antigens and the immune response against the cancer cells is initiated.

Question 7

Trafficking of T-cells to tumours (C T L s)

Answer 7

The activated T-cells move through the blood vessels to the site of the tumour.

Question 8

Infiltration of T-cells into tumours (C T L s, endothelial cells)

Answer 8

Once the T-cells reach the cancerous cells, they invade the tumour to attack it.

Question 9

Recognition of cancer cells by T-cells (C T L s, cancer cells)

Answer 9

T-cells recognize cancer cells because of the antigens they had previously released.

Question 10

Killing of cancer cells (immune & cancer cells)

Answer 10

T-cells initiate a pathway that results in cancer cell death.

Question 11

theory of immunosurveillance

Answer 11

states that tumour cells are identified and kept under
control by the immune system of healthy individuals.

Question 12

what do cancer cells do about the immunosurveillance

Answer 12

cancer cells sometimes evade recognition by the immune system, or the magnitude of the
anti-tumour immune response is not sufficient to kill all of the cancer cells

Question 13

what is immunoediting (what does it describe)

Answer 13

describes the connection between the tumour cells and the
immune system in the context of immunosurveillance and tumour progression.

Question 14

what is immunoediting

Answer 14

during cancer evolution there is ongoing cross-talk between the cancer cells and the immune cells
- immune destroys the growing cancer cells, but this promotes tumor growth

Question 15

how many phases does immunoediting include 3.

Answer 15

• elimination
• equilibrium
• escape

Question 16

phase 1: elimination

Answer 16

When a tumour cell arises in a tissue, the immune system can quickly act to remove it

Question 17

what cells are involved in phase 1

Answer 17

N K cells, cytotoxic T-cells, and helper T-cells

Question 18

phase 2: equilibrium

Answer 18

If the tumour cells are not eliminated, they can enter a state of equilibrium where the cell proliferation
is matched by cell killing by the immune system

Question 19

how long does the equilibrium stage last?

Answer 19

short time or many years

Question 20

phase 3: escape

Answer 20

tumour cells are no longer recognized by the immune system and so avoid
elimination. These cells are able to grow uncontrolled and eventually proliferate to form a tumour

Question 21

what are the 2 ways tumor cells use to avoid detection by the immune system

Answer 21

reduced MHC expression
poor costimulatory molecules

Question 22

Reduced M H C Expression

Answer 22

Tumour cells display low levels of MHC class I molecules on their cell surface.
- As cytotoxic T
lymphocytes recognize antigens in the context of MHC class I molecules
an absence of these molecules will inhibit recognition of tumour cells.

Question 23

poor costimulatory molecules

Answer 23

T-cells require both expression of MHC and costimulatory molecules to become activated.
- Tumour cells
lack these costimulatory molecules, which contribute to their poor immunogenicity. T-cells will only be
partially activated