Cancer

Question 1

What is neoplasia?

Answer 1

Too much cell growth (cell division).
Can lead to formation of tumours.

Question 2

What does too much cell death without compensating cell division lead to?

Answer 2

Wasting / neurological diseases.

Question 3

What are the 3 main categories of extrinsic factors involved in the cause of cancer?

Answer 3

• Radiation
• Chemical
• Tumour Viruses

Question 4

What are the 5 types of radiation associated with the development of cancer?

Answer 4

• UV Radiation
• Radon
• Gamma Radiation
• Ionising Radiation
• Nuclear Radiation

Question 5

What are the 6 main chemical factors that contribute to the development of cancer?

Answer 5

• Asbestos
• Smoking / Vaping
• Alcohol
• Aflatoxin B
• Benzopyrene
• Vinyl Chloride

Question 6

What are the 2 types of intrinsic factors associated with development of cancer?

Answer 6

• Inherited germ-line mutation in tumour supressor genes.
• Inherited germ-line mutation in DNA repair genes.

Question 7

How may ionising radiation cause cancer?

Answer 7

Carcinogen but relatively poor mutagen.
Causes chromosomal damage (clastogenic), which can lead to gain of oncogene / loss of tumour supressor.

Question 8

How may gamma radiation cause cancer?

Answer 8

DOES NOT INTERACT DIRECTLY WITH DNA.
- Produces superoxide radicals which can damage DNA.
- Anti-oxidants thought to reduce risk of cancer: they interact with superoxide radicals.

Question 9

How does ultraviolet radiation interact with our DNA to cause cancer?

Answer 9

Causes pyrimidine dimer formation which can lead to mutations if not repaired by DNA repair systems.

Question 10

How are most chemical carcinogenic factors associated with development of cancer?

Answer 10

• Metabolites can react with DNA to cause mutations, particularly in p53, RAS and EFGR.

Question 11

How does Human Papilloma Virus (HPV) cause cancer?

Answer 11

Disrupts Rb and p53 (controls G2 to mitosis) pathways that control cell proliferation.

Question 12

What is the Ames test?

Answer 12

Test for mutagenic potential (mutagen not necessarily a carcinogen, carcinogen does not have to be mutagenic - often is though).

Question 13

The Rous Sarcoma Virus oncogene (SRC) encodes a protein. What activity does this protein have?

Answer 13

Tyrosine Kinase

Question 14

What are the 3 main proto-oncogenes?

Answer 14

RAS, MYC and SRC

Question 15

What are the 3 main tumour suppressor genes?

Answer 15

TP53, Rb, APC (Adenomatous polyposis coli)

Question 16

What is the Philadelphia Chromosome and how does it cause Chronic Myelogenous Leukaemia (CML)?

Answer 16

• Results from ionising radiation (chromosomal damage)
• Example of chromosomal translocation (segments of two non-homologous chromosomes are exchanged).
• ABL gene (chromosome 9), BCR gene (chromosome 22).
• BCR-ABL construct leads to overproliferation.

Question 17

Not as fussy…

Why are athymic mice useful for testing tumour growth in vivo?

Answer 17

They don’t reject transplanted cells.