10. Neoplasia III - How and Why?

Question 1

What are 5 extrinsic factors that increase chances of developing cancer?

Answer 1

High BMI
Low fruit/veg diet
Lack of exercise 
Tobacco use
High alcohol intake

Question 2

In what order must initators and promotors be exposed to, to cause cancer?

Answer 2

Initiators then promotors

Question 3

Which out of initiators and promotors are an example of a mutagen?

Answer 3

Initiators are a mutagen

Question 4

Which out of initiators and promotors cause proliferation of neoplastic cells?

Answer 4

Promotors cause proliferation

Question 5

Where do chemicals that are pro carcinogens undergo conversion to become carcinogens?

Answer 5

The cytochrome p450 enzymes in the liver

Question 6

Name examples of radiation that can increase the chance of developing cancer?

Answer 6

UV Light
X Rays
Gamma rays
Alpha particles
Beta particles

Question 7

How is radon gas from rocks be harmful?

Answer 7

Radon breaks down to release beta particles

Question 8

In terms of molecules what does the HPV (human papillomavirus) express that can lead to cancer formation and why?

Answer 8

E6 - inhibits P53, the guardian of the genome (leads to errors in DNA)
E7 - inactivates pRB allows cell to pass through restriction point in cell cycle

Question 9

How do hepatitis B and C viruses lead to cancer?

Answer 9

Cause chronic liver injury via inflammation

This leads to massive hepatocyte regeneration which leads to an increased chance of mutation occurring

Question 10

How does HIV lead to cancers forming?

Answer 10

Compromises immune system leading to carcinogenic infections to occur

Question 11

Using the 2 hit theory explain why people with an inherited predisposition to a cancer are more likely to get it than someone without the predisposition?

Answer 11

In familial cancers the 1st hit is delivered via the gear line hence every cell has it, therefore only 1 more hit is required which is much more likely than in sporadic cancers where 2 hits are required on the same cell

Question 12

Tumour suppressor genes do what to tumour growth when activated?

Answer 12

Inhibit tumour growth

Question 13

How many alleles need to be mutated for tumour suppression genes to not work properly?

Answer 13

Both alleles

Question 14

What do proto-oncogenes do to tumour growth when activated?

Answer 14

They become oncogenes and stimulate tumour growth

Question 15

How many proto-oncogenes need to be activated to stimulate tumour growth

Answer 15

Only 1 needs to become an oncogene

Question 16

Roughly how many mutations are needed in progression to for a fully evolved neoplasm?

Answer 16

10

Question 17

What is progression?

Answer 17

The sequence in which neoplastic cells obtain multiple more mutations making them more malignant

Question 18

What are the 6 hallmarks of cancer?

Answer 18

Self sufficiency in growth signal
Resistance to stop signals
Immortalisation
Sustained ability to induce new blood vessels
Resistant to apoptosis
Ability to invade and metastasise

Question 19

What are 3 intrinsic factors that increase the chance of developing cancer?

Answer 19

Age
Sex
Hereditary