Cancer

Question 1

What is a carcinoma?

Answer 1

Disorderly growth of epithelial cells that invade adjacent tissues and spread vis the lymphatics and bloodstream to other parts of the body.

Question 2

What does it mean that most cancers are monoclonal?

Answer 2

They are derived from a single cell mutation.

Question 3

How to cancer cells grow and divide?

Answer 3

Mitosis

Question 4

How do some cancer cells escape chemotherapy treatment?

Answer 4

They hide within the non proliferating stage of mitosis and then recover and re-cycle in the body later on.

Question 5

Give some properties of cancer cells?

Answer 5

Increased growth factor secretion
Increased oncogene expression
Loss of contact inhibition
Loss of tumour suppressor genes. 
Frequent mitoses

Question 6

What are oncogenes?

Answer 6

Genes that programme for cancer. Accelerate cell division.

Question 7

Which type of cancer normally causes the death in a patient?

Answer 7

Cancer that has metastases rather than the primary cancer.

Question 8

What are some causes of cancer

Answer 8

Chemical carcinogens
Physical carcinogens
Viral carcinogens
Growth factors 
Oncogenes
Metastasis

Question 9

Give some examples of a chemical carcinogen?

Answer 9

Polycyclic hydrocarbons
Nitrogen mustard
Alcohol and smoking

Question 10

Give some examples of physical carcinogens?

Answer 10

Ionising radiation

Mechanism - chromosome translocation, gene amplification, oncogene activation.

Question 11

Give some examples of viral carcinogens?

Answer 11

Herpes virus
Papillomavirus
Retroviruses
Hepatitis B

Question 12

What do oncogenes do?

Answer 12

Involved in the promotion of cancer. They are transformed genes and promote the positive regulators for growth.

Question 13

Give some examples of growth factors?

Answer 13

Polypeptide molecules.

VEGF - vascular endothelial growth factor.

Question 14

What is the normal function of a tumour suppressor gene?

Answer 14

Acts as a transcriptional regulator:
Promotes DNA repair, apoptosis and cell differentiation.
The cell’s brakes for cell growth.

Question 15

How do cancer cells induce the alteration of tumour suppressor genes?

Answer 15

Induced by DNA damage and hypoxia

Question 16

What are the properties if metastasis?

Answer 16

Not random
Cascade of limited sequential steps
Involves humour-host interactions
Survival of the fittest pertains

Question 17

What are the main stages within invasion and metastasis?

Answer 17

Tumour invades through the basement membrane.
Moves into extracellular matrix/connective tissue/surrounding cells
Invades blood vessels
Tumour cells ‘arrested’ in distant organ

Question 18

What is angiogenesis?

Answer 18

The formation of new blood vessels.

Question 19

What is the role of angiogenesis in cancer.

Answer 19

Key factor in the maintenance and progression of malignant tumours.
A new blood vessel must form before a tumour can reach < 2mm in diameter.
It also provides a route for the cancer to spread and enter the circulatory system.

Question 20

What is the role of VEGF?

Answer 20

VEGF normally binds to receptors one the surface of vascular endothelial cells. This binding activates the signalling pathways that lead to growth, proliferation and migration of endothelial cells - increasing cancer.

Question 21

What is the function of Avastin?

Answer 21

Avastin is an anti-VEGF drug that prevents VEGF from interacting with its receptors. ultimately leads to a reduction in microvascular growth, inhibits progression of metastatic disease and reduces intratumoral pressure, which may improve the delivery of cytotoxic agents.

Question 22

What percentage of cancer patients have metastases?

Answer 22

65%

Question 23

How does the immune system not recognise foreign cancer cells?

Answer 23

Cancer cells can hide from T cells by the PDL-1 ligand on tumour cells binding with PD1 (programmed death receptor) on T lymphocytes. This suppresses the T cells and they become blinded.

Question 24

Where do somatic mutations occur?

Answer 24

Occur in nongermline tissues
Are nonheritable
E.g breast

Question 25

Where do germline mutations occur?

Answer 25

Present in egg or sperm Are heritable Cause cancer family syndromes (All cells affected in offspring)

Question 26

What is a Proto-oncogene?

Answer 26

Normal gene that codes for proteins to regulate cell growth and differentiation.

Question 27

What is the two-hit hypothesis?

Answer 27

Cancer arises when both brakes fail | Cancer is the result of accumulated mutations to a cell's DNA. Both genes need to be affected.

Question 28

What is the role of MisMatch Repair (MMR)?

Answer 28

Corrects errors that spontaneously occur during DNA replication like single base mismatches or short insertions and deletions.

Question 29

What is micro satellite instability?

Answer 29

MSI is the phenotypic evidence that MMR is not functioning normally.

Question 30

Define benign?

Answer 30

Lacks ability to metastasize. Rarely or never become cancerous. Can still cause negative health effects due to pressure on other organs.

Question 31

What is a dysplastic tumour?

Answer 31

‘Benign’ but could progress to malignancy. | Cells show abnormalities of appearance & cell maturation. Sometimes referred to as ‘pre-malignant’.

Question 32

Define malignant?

Answer 32

Able to metastasize.

Question 33

What are de novo mutations?

Answer 33

New mutations that occur within the germ cell of the parent. No family history of hereditary cancer syndrome

Question 34

What are some features of retinoblastoma?

Answer 34

Most common eye tumour in children. | Occurs in heritable and nonheritable forms

Question 35

What are the risk factors for breast cancer?

Answer 35

``` Ageing Family history Early menarche Late menopause Nulliparity - not had children Oestrogen use Dietary factors (eg: alcohol) Lack of exercise ```

Question 36

What are the risk factors for colorectal cancer?

Answer 36

``` Ageing Personal history of CRC or adenomas High-fat, low-fibre diet Inflammatory bowel disease Family history of CRC ```