Neoplasia 3

Question 1

What are the 5 leading behavioural and dietary risk factors for cancer?

Answer 1

High BMI
Low fruit and veg intake 
Lack of physical activity 
Tobacco use
Alcohol use

Question 2

What percentage of cancer risk do we attribute to the environment?

Answer 2

85%

Question 3

What are the 3 main categories for extrinsic carcinogens?

Answer 3

Chemicals
Radiation
Infections

Question 4

What is 2-napthylamine?

Answer 4

Dye

Causes bladder cancer

Question 5

What did the dye industry end up proving about cancer?

Answer 5

There is a long delay between carcinogen exposure and malignant neoplasm onset
Risk of cancer depends of total carcinogen dosage
There is sometimes organ specificity for particular carcinogens

Question 6

What does the Ames test show?

Answer 6

Initiators are mutagens
Promoters cause prolonged proliferation in target tissues
Culminates in monoclonal expansion of mutant cells

Question 7

What type of carcinogens are present in cigarette smoke?

Answer 7

Polycyclic aromatic hydrocarbons

Question 8

What type of carcinogens are in dye?

Answer 8

Aromatic amines

Question 9

What type of carcinogens can be generated by the stomach?

Answer 9

N-nitroso compounds

Question 10

What type of carcinogens is vinyl chloride?

Answer 10

Alkylating agents

Question 11

How are procarcinogens converted to carcinogens?

Answer 11

Cytochrome P450 enzymes in the liver

Question 12

What is a complete carcinogen?

Answer 12

One that acts as an initiator and promoter

Question 13

What is radiation?

Answer 13

Any type of energy travelling through space

Question 14

What does ionising radiation do?

Answer 14

Strips electrons from atoms

Question 15

What direct DNA damage can be caused by radiation?

Answer 15

Altered bases

Single/double strand DNA breaks

Question 16

How is indirect DNA damage caused by radiation?

Answer 16

free radical formation

Question 17

How can infections be directly carcinogenic?

Answer 17

Affects genes that control cell growth

Question 18

How can infections be indirectly carcinogenic?

Answer 18

Cause chronic tissue injury

Resulting regeneration acts as a promoter or may cause new mutations

Question 19

Which cancer is HPV strongly linked to?

Answer 19

Cervical cancer

Question 20

How does HVP act as a direct carcinogen?

Answer 20

Expresses E6 and E7 proteins
E6 inhibits p53
E7 inhibits pRB protein function

Question 21

Helicobacter pylori increases risk of …

Answer 21

Gastric carcinoma

Question 22

Describe the RAS proto-oncogene

Answer 22

Encodes a small G protein that signals to push the cell past the cell cycle restriction point
Mutated in approx 1/3 of all malignant neoplasms

Question 23

Describe the RB gene

Answer 23

Restrains cell proliferation by inhibiting passage through the restriction point
Inactivation of the RB gene allows unrestrained passage through restriction point

Question 24

Name some of the many things that proto-oncogenes can encode

Answer 24

Growth factors
Growth factor receptors
Signal transducers (RAS) 
Intracellular kinases
Transcription factors
Cell cycle regulators 
Apoptosis regulators

Question 25

What is xeroderma pigmentosum?

Answer 25

Autosomal recessive condition Mutations in DNA repair genes Cannot perform nucleotide excision repair Patient very sensitive to UV damage

Question 26

What is hereditary non-polyposis colon cancer syndrome?

Answer 26

Mutation affects one of several DNA mismatch repair genes Autosomal dominant Associated with colon carcinoma

Question 27

Which genes are linked to familial breast carcinoma and what are their usual functions?

Answer 27

BRCA1 and BRCA 2 | Usually important for repairing double stranded DNA breaks

Question 28

What do we call the genes that maintain genetic stability?

Answer 28

``` Caretaker genes (A class of tumour suppressor genes) ```

Question 29

What is cancer progression?

Answer 29

A steady accumulation of multiple mutations

Question 30

What are the 6 hallmark cellular behaviours for cancer cells?

Answer 30

Self sufficiency in growth signals Resistance to anti-growth signals No limit to number of times a cell can divide Sustained ability to induce new blood vessels Resistance to apoptosis Ability to invade and produce metastases

Question 31

What is Burkitt's lymphoma?

Answer 31

``` B cell lymphoma Associated with Epstein-Barr virus (EBV) and malaria Activation of an oncogene MYC gene Most commonly affects children ```

Question 32

What is familial adenomatous polyposis?

Answer 32

Mutations in APC gene Rare Autosomal dominant Numerous adenomas develop at an early age - almost inevitable progression to adenocarcinomas

Question 33

Most cases of hepatocellular carcinoma are secondary to something. What can those things be?

Answer 33

Viral HepB or HepC Metabolic toxins (aflatoxin/alcohol) Endogenous toxins (haemochromatosis) Chronic liver disease