Outline of the Disease Process

Question 1

What are the characteristics of cancer cells?

Answer 1

• loss of contact inhibition
• increase in growth factor secretion
• increase in oncogene expression
• loss of tumour suppressor genes

Question 2

What are the characteristics of a normal cell?

Answer 2

• oncogene expression is rare
• intermittent or co-ordinated growth factor secretion
• presence of tumour suppressor genes

Question 3

What are the 3 stage of cancer?

Answer 3

• initiation
• promotion
• progression

Question 4

What causes initiation?

Answer 4

• chemical
• physical
• viral

Question 5

What causes promotion of cancer?

Answer 5

• growth factors

- oncogenes

Question 6

What causes progression of cancer?

Answer 6

-metastasis

Question 7

What are some examples of chemical carcinogens?

Answer 7

• soot and tar
• aniline dyes
• aflatoxin
• nitrogen mustard
• alcohol and smoking

Question 8

What are some examples of physical carcinogens?

Answer 8

Ionising radiations:
-dose-response relationship
-radon source is mainly buildings
-increased risk by smoking
-ventilation reduced risk
Mechanism
-chromosome translocation
-gene amplification
-oncogene activation

Question 9

What are some examples of viral carcinogens?

Answer 9

• herpes
• HPV
• retroviruses
• hep B

Question 10

What are growth factors?

Answer 10

• polypeptide molecules
• regulate cell growth and function
• bind to cell membrane receptors
• stimulate activation of intracellular signal transduction pathways

Question 11

Stimulation may be…

Answer 11

Autocrine
-cell carries receptor and secretes growth factor
-cell escapes normal control mechanism
Paracrine
-GFs acting on a cell are produced locally by the cell or its immediate neighbours

Question 12

What is p53?

Answer 12

• tumour suppressor gene
• most commonly altered gene in human tumours
• normal function is as transcriptional regulator which promotes DNA repair, apoptosis and differentiation
• G1/S checkpoint control gene

Question 13

What induced p53?

Answer 13

• DNA damage

- hypoxia

Question 14

Describe metastasis.

Answer 14

• not random
• cascade of limited sequential steps
• involves tumour-host interactions
• survival of the fittest pertains

Question 15

How does a tumour metastasise?

Answer 15

-Invades through basement membrane
-moves into extracellular matrix/connective tissue/surrounding cells
-invades blood vessels
tumour cells arrested in distant organ

Question 16

What enzymes are involved in cell adhesion?

Answer 16

• cahedrins
• integrins
• CD44

Question 17

What enzymes are involved in ECM?

Answer 17

• matrix metalloprotinases
• plasmin]
• cathespin

Question 18

What is angiogenesis?

Answer 18

the formation of new blood vesssels

Question 19

Give an example of a growth factor.

Answer 19

VEGF vascular endothelial growth factor

Question 20

What does the anti-VEGF antibody avastin do?

Answer 20

• prevents interaction with receptors and activation of downstream signally pathways
• normalises vasculature

Question 21

Why does our immune system not recognise foreign cancer cells?

Answer 21

• cancer cells can hide from T cells
• PD1 present on T lymphocytes
• ligand PD1 on tumour cells
• interaction of these suppresses T cell action