Angiogenesis

Question 1

What is the non-neoplastic element of a neoplasm?

Answer 1

Stroma

Question 2

What does the stroma contain?

Answer 2

Blood vessels to supply nutrients to the tumour
Fibroblasts
Variety of inflammatory cells

Question 3

What is continued growth of a tumour dependent on?

Answer 3

An adequate blood supply to provide oxygen and nutrients

It also allows tumour cells to gain access to the vessels and the development of metastasis

Question 4

What happens to a tumour if it does not have an adequate blood supply?

Answer 4

Necrosis

Question 5

What are the roles of the two types of tumour associated macrophages?

Answer 5

M1 - primarily tumoricidal = fight tumour growth

M2 - help tumour growth

Question 6

What is metastasis?

Answer 6

Transmission of microorganisms or cancerous cells from an original site to one or more sites elsewhere in the body, usually by way of the blood vessels or lymphatics

Question 7

Describe the 4 stages of metastasis

Answer 7

1. Intravasation - digestion of basement membrane
2. Tumour cells must evade the immune system by forming small clusters
3. Extravasation - invade a basal lamina, grow, form blood vessels
4. Extravascular tumour

Question 8

Compare the main features of benign and malignant tumours

Answer 8

Benign - slow growth, demarcation, resembles original architecture
Malignant - fast growing, invades locally, metastasis, anaplasia, resembles original architecture

Question 9

What are carcinogenic agents, give some examples

Answer 9

Agents which cause tumours - cause malignant transformation in cells
- Chemicals, irradiation, infectious agents

Question 10

What is an oncogene?

Answer 10

Drives neoplastic transformation in the organism

Question 11

What is a proto-oncogene?

Answer 11

A normal cellular gene that regulates cell cycle activation

Question 12

How are oncogenes activated?

Answer 12

1. By viral-oncogenes - present in the viral DNA/RNA, infection with these leads to an oncogene
2. DNA damage or mutation of a proto-oncogene

Question 13

Carcinogens are electrophiles, what is an electrophile?

Answer 13

Structures that are have electron deficient atoms

Question 14

What 2 steps are undertaken by chemical carcinogens?

Answer 14

Initiation - Carcinogens introduce an irreversible change

Promotion - the damaged DNA template must be replicated so that the change in DNA becomes fixed

Question 15

What are promotors?

Answer 15

Agents that stimulate the division of mutated cells

Question 16

Give an example of a promotor

Answer 16

Oestrogen binding to cell receptors, stimulates growth of neoplasms in humans

Question 17

What is radiation?

Answer 17

Energy that travels in the form of waves

Question 18

What are the two types of radiation?

Answer 18

Non-ionising: Not enough energy to displace bound electrons from atoms
Ionising: Sufficient energy to release electrons in a reaction cascade

Question 19

What are the consequences of high or low doses of radiation?

Answer 19

High - extensive necrosis affecting more rapidly dividing cells
Low - accumulative effects, DNA damage, apoptosis, tumours

Question 20

Which types of non-ionising radiation has a direct action on DNA?

Answer 20

UVB

Question 21

Give some examples of

DNA virsuses

Answer 21

Papovavirus
Herpesvirus
Adenovirus

Question 22

Describe a viral DNA malignant neoplasm

Answer 22

Viral genome is integrated into the host genome, only part of the viral cycle is completed

• suppression of hosts immune system
• activation of cellular oncogenes

Question 23

What is the role of tumour suppressor genes?

Answer 23

Normal cellular genes that regulate cell cycle activation

- control cell cycle, apoptosis and DNA repair throughout the cell cycle