Revision of Cancer Biology

Question 1

What are the most common causes of cancer deaths?

Answer 1

Breast
Prostate
Lung
Bowel

Question 2

What are the hallmarks of cancer cells?

Answer 2

• growth signal not required for cell survival, growth and differentiation
• unresponsiveness to growth-inhibitory signals
• evasion of apoptosis
• defects in DNA repair
• cells become immortal (limitless reproduction potential)
• ability to invade and metastasise
• angiogenesis sustained and increased

Question 3

What types of mutations involve proto-oncogenes?

Answer 3

• translocation/transposition
• gene amplification
• point mutations

Question 4

What translocations/transpositions involve proto-oncogenes?

Answer 4

• new promotor added to gene switching the gene on = abnormal growth
• Bcl2 is anti-apoptotic
• overexpression of t14:18, q32:21
• leads to follicular lymphoma

Question 5

What is an example of gene amplification?

Answer 5

• HER2/ErB2
• overexpression of GF
• invasive breast carcinoma

Question 6

What are 2 examples of point mutations?

Answer 6

In a gene/coding region (c-H-ras) or non-coding region (c-Fos)

Question 7

What is point mutation occurring within a coding region?

Answer 7

• occurs within the gene:
• c-H-ras
• glycine to valine
• bladder cancer

Question 8

What is a point mutation occurring in a non-coding region?

Answer 8

• occurs in non-coding region (promoter/enhancer region)
• c-Fos (TF)
• melanoma

Question 9

How are oncogenes dominantly active?

Answer 9

• GF
• receptors
• signal transduction proteins
• TF
• pro/anti-apoptotic proteins

Question 10

What are some examples of GF oncogenes?

Answer 10

• EGF

- HER2

Question 11

What are some examples of GF receptor oncogenes?

Answer 11

• EGF

- VEGF

Question 12

What are some examples of signal-transduction proteins?

Answer 12

• KRAS

- B-Raf

Question 13

What are some examples of TF oncogenes?

Answer 13

c-mvc

Question 14

What are some examples of anti-apoptotic protein oncogenes?

Answer 14

Bcl-2

Question 15

How do tumour suppressor genes work?

Answer 15

• loss of function
• point mutations
• divided into gatekeeper genes, caretaker genes and pro-apoptotic genes

Question 16

How do tumour suppressor genes allow protein mutations?

Answer 16

• within control element (Bax which is an anti-apoptotic protein)
• within gene (P53 which is genome guardian preventing cells leaving G1)

Question 17

What are examples of gatekeeper tumour suppressor genes?

Answer 17

p53

pRb

Question 18

What are examples of caretaker tumour suppressor genes?

Answer 18

BRCA

MMR

Question 19

What are examples of pro-apoptotic genes?

Answer 19

Bax

Question 20

What are the types of DNA damage?

Answer 20

• oxidation of bases (reactive oxygen species = DNA strand interruptions)
• alkylation of bases (methylation)
• hydrolysis of bases (deamination, depurination, depyrimidination)
• Bulky adduct formation
• mismatch of bases (DNA replication errors)

Question 21

What are the clinical features of benign tumours?

Answer 21

• slow growing but progressive (rare mitotic figures)
• non-invasive
• non-metastasising
• well differentiated

Question 22

What are the clinical features of malignant tumours?

Answer 22

• fast growing
• numerous and abnormal
• ulcerate of surface
• local invasion
• may metastasise
• may see weight loss, anorexia, anaemia