Outline of Disease Process CANCER

Question 1

What does “cancers are mostly monoclonal” mean?

Answer 1

Mainly arise from one cell

Question 2

Whats different about cancer cells?

Answer 2

Increased growth factor secretion
Increased in oncogene expression
Loss of tumour supressor genes
Loss of contact inhibition

Question 3

What are the 5 steps of carcinogenesis?

Answer 3

Carcinogen
Initiation
Promotion
Tumour Growth
Progression

Question 4

What is a diagnostic threshhold?

Answer 4

Size at which a cancer becomes clinically detectable

Question 5

What are the 3 types of carcinogens?

Answer 5

Chemical
Physical
Viral

Question 6

What chemical carcinogen causes liver cancer?

Answer 6

Aflatoxin (in mouldy peanuts)

Question 7

Most common chemical carcinogens?

Answer 7

Smoking & alcohol

Question 8

Physical carcinogen?

Answer 8

Ionising radiation

Question 9

How does ionising radiation cause cancer?

Answer 9

• Translocate chromosomes
• Amplify certain Genes
• Activate Oncogenes

Question 10

What viral carcinogen causes burkitts lymphoma?

Answer 10

Herpes virus

Question 11

What viral carcinogen caues liver cancer?

Answer 11

HEP B

Question 12

What 3 things are involved in the promotion stage?

Answer 12

Oncogenes
Tumour suppressor genes
Growth factors

Question 13

How do oncogenes promote the progression stage?

Answer 13

Positive growth regulators, stimulate tumour growth

Question 14

How do growth factors stimulate cell growth?

Answer 14

Bind to cell-membrane receptors & activate intracellular signal transduction pathways

Question 15

Whats the difference between autocrine & paracrine signalling?

Answer 15

Paracrine signalling - signals act on nearby cells
Autocrine - signals acting on the same cell that produces them

Question 16

Whats the normal function of tumor suppressor genes?

Answer 16

Promoting:

DNA repair
Apoptosis
Differentiation

Question 17

What normally induces tumor suppressor genes to act?

Answer 17

Hypoxia & DNA damage

Question 18

Name a tumor supressor gene

Answer 18

P53

Question 19

How does progression (metastasis) occur?

Answer 19

Tumour invades through basement membrane
Invades ECM/CT/other cells
Invades blood vessels
Cells arrested in distant tissue

Question 20

Describe the progression stage

Answer 20

Series of limited sequential steps involving host-tumour interactions

Question 21

At what point is angiogenesis vital for continued tumor growth?

Answer 21

New vessels must form for a tumour to grow beyond 2mm in diameter

Question 22

How does angiogenesis affect the ECM?

Answer 22

Enzymes degrade ECM to allow for new vessel growth

Question 23

How is angiogenesis related to cancer severity?

Answer 23

Higher density of blood vessels, more severe tumour malignancy/metastasis

Question 24

How is angiogenesis inhibited?

Answer 24

Avastin (anti-VEGF antibody) binds to VEGF
Prevents VEGF-receptor interaction

(VEGF = Vascular endothelial growth factor)

Question 25

What is the ultimate effect of anti-VEGF treatments?

Answer 25

Vascular regression & dormant tumours

Question 26

What is the purpose of T cell inhibition receptors?

Answer 26

Maintain self-tolerance & protect tissue during immune responses

Question 27

How do tumours blind T cells?

Answer 27

Express specific ligand and bind to T cell inhibition receptors

Question 28

What ligand/receptor combo is used by cancers to blind T cells?

Answer 28

ligand on cancer cell = PDL-1 Receptor on T cell = PD1

Question 29

Explain therapeutic options to bypass T cell blindness to cancer cells?

Answer 29

Block PDL-1 on cancer cell or PD1 on T cell Modified artificial T cells - CAR T cells (chimeric antigen receptors)

Question 30

What is Epithelial Mesenchymal Transition (EMT)

Answer 30

Conversion of connected epithelial cells to independent mesenchymal cells Enables the ability to move and invade local environment Reversible Occurs in Embryogenesis, cancer metastasis

Question 31

What is the function of integrin

Answer 31

Allows cells to become mobile

Question 32

What is the function of proteases in cancer

Answer 32

Creates Pathway through ECM Matrix Metalloproteins Contributes to loss of cell junctions