Aetiology of Cancer & Cancer Treatment

Question 1

What is the somatic mutation theory of cancer?

Answer 1

I. Cancer is derived from a single somatic cell that has accumulated multiple DNA mutations.
II. The default state of cell proliferation is quiescence (dormancy)
III. Cancer is a disease of cell proliferation caused by mutations in genes that control proliferation and the cell cycle

Question 2

List 4 chemical carcinogens and the tissue they primarily affect.

Answer 2

tobacco smoke (lung)
alcohol (oesophageal)
radon gas (lung)
asbestos (mesothelioma)

Question 3

List 3 different cancer causing infections.

Answer 3

HPV (cervical cancer)
Hepatitis B (liver cancer)
H.pylori (stomach cancer)

Question 4

Name 4 types of mutations involved in cancer

Answer 4

Point mutations
DNA rearrangements
Gene amplification
Chromosomal translocation

Question 5

What are point mutations?

Answer 5

single amino acid changes, common in Ras oncogene

Question 6

How many genes are there in the genome and how many are oncogenes/tumour supressor genes.

Answer 6

approx 40,000 genes approx 80 oncogenes

15 tumour suppressor genes

Question 7

What are the four gene groups that are damaged in cancer? (give example of gene in each group)

Answer 7

Oncogenes (myc, ras)
Tumour suppression genes (Rb)
Apoptosis genes (BCL-2)
DNA repair genes (BRCA-1/-2)

Question 8

What gene changes are identified in colon cancer?

Answer 8

Cell adhesion (APC)
Signal transduction (K-ras) 
Proliferation/differentiation (SMAD) 
DNA repair (p53, MSH2, MLH1)

Question 9

What does CLL stand for??

Answer 9

Chronic Lymphocytic Leukaemia

Question 10

What does AML stand for?

Answer 10

Acute Myeloid Leukaemia

Question 11

What does CML stand for?

Answer 11

Chronic Myeloid Leukaemia

Question 12

What does ALL stand for?

Answer 12

Acute Lymphocytic Leukaemia

Question 13

What are adenomatous cells?

Answer 13

ductal or glandular cells

Question 14

What are squamous cells?

Answer 14

flat cells

Question 15

What are the advantages associated with using cells in experimental models?

Answer 15

Growth not inhibited by cell contact
No requirement for adhesion
Proliferation is unlimited (effectively immortal)

Question 16

What are the advantages associated with using cells in experimental models?

Answer 16

Different lines derived from same type of tumour have different properties
Not looking at whole tissue/organism

Question 17

What are the three types of models used to study cancer experimentally?

Answer 17

Cell, Animal, Human

Question 18

What can lead to the inhibition of oestrogen production?

Answer 18

removal/inhibition of ovarian function

post-menopausal aromatase inhibitors

Question 19

How does hormone therapy work in breast cancer?

Answer 19

80% of breast cancers express oestrogen receptor.

Oestrogen receptor blockers, like tamoxifen, prevent oestrogen binding to ER.

Question 20

How does hormone therapy work in prostate cancer?

Answer 20

Prostate tissue depends on testosterone.
Removal of testosterone leads to regression in 80% of cases.
This can occur through orchidectomy, testicular function inhibitors and androgen receptor blockers .