More disorders of tissue growth

Question 1

How do benign and malignant tumours compare in terms of growth rate?

Answer 1

Benign - slow

Malignant - fast

Question 2

How do benign and malignant tumours compare in terms of demarcation (growth limits)

Answer 2

Benign tumours may reach limit

Malignant have no limit

Question 3

How do benign and malignant tumours compare in terms of invasion?

Answer 3

Benign - no invasion

Malignant - invasion

Question 4

How do benign and malignant tumours compare in terms of resemblance to original architecture?

Answer 4

Benign resemble original tissue

Malignant may or may not resemble original tissue

Question 5

How do benign and malignant tumours compare in terms of anaplasia?

Answer 5

Benign have no anaplasia

Malignant may or may not have anaplasia

Question 6

Give 5 examples of how malignant and benign tumours differ

Answer 6

Benign - localised, expansile growth, stroma produced by neighbouring cells, growth limit, resemble original tissue, no metastasis
Malignant - infiltrative growth, produce own stroma, may not resemble original tissue, metastasise, no growth limit

Question 7

What are tumour associated macrophages?

Answer 7

Macrophages present in tumours
M1 = tumoricidal (better prognosis)
M2 = relevant role

Question 8

What is an oncogene?

Answer 8

A gene that drives neoplastic transformation

drive tumour development

Question 9

What is a proto-oncogene?

Answer 9

Normal cellular gene that regulates the cell cycle

Question 10

What is a viral-oncogene?

Answer 10

Oncogene in virus DNA/RNA

Infection with virus causes it to become an oncogene

Question 11

What are carcinogenic agents? What type of agents are they?

Answer 11

Agents that cause malignant neoplasia in cells

Chemicals, irradiation, infectious agents

Question 12

Carniogenic agents can be direct or indirect. What do these terms mean?

Answer 12

Direct - need no chemical transformation (ultimate carcinogens)
Indirect - need chemical transformation, usually metabolised in the liver (pro-carcinogens)

Question 13

Both indirect and direct carcinogenic agents are highy reactive what? What do they do?

Answer 13

Electrophiles

Bind to DNA/RNA/protiens to form covalent bond

Question 14

Chemical carcinogenesis requires 2 steps. What are these?

Answer 14

Initiation - irreversible genetic change

Promotion - damaged DNA replicates so change becomes fixed

Question 15

What are promoters? What do they do?

Answer 15

Regions of DNA that initiate transcription of a gene

Stimulate division of mutated cells

Question 16

Give examples of promoters

Answer 16

Carcinogens 
Radiation 
Viruses
Hormones 
Parasites
Dietary factors

Question 17

Give an example of a direct carcinogen and an indirect carcinogen

Answer 17

Direct - anticancer drug

Indirect - tobacco

Question 18

How do different doses of radiation damage cells?

Answer 18

Low dose - DNA damage
Mild dose - repair or tumor
High dose - apoptosis

Question 19

Radiation can be ionising or non-ionising. What do these terms mean? Give an example of each

Answer 19

Ionising - not enough energy to displace electrons from atoms e.g. UV
Non-ionising - enough energy to displace electrons from atoms e.g. X-rays

Question 20

Give an example of a hormone that increase risk of tumours.

Answer 20

Oestrogen - increased risk of mammary tumours

Question 21

Mutated cells can lead to increased function of loss or function. What type of genes cause each of these?

Answer 21

Non-functioning - by tumour or suppressor gene

Functioning - by growth promoting or normal gene

Question 22

When are cells checked for damage or unduplicated DNA?

Answer 22

Only if proliferating

Question 23

Tumours have a limitless reactive potential. What is this?

Answer 23

Normal cells stop replicating after certain time length due to shortening of telomeres at end of chromosome
Tumour and stem cells have telomerase - maintain normal telomere length and allow continued replication

Question 24

Which individuals are more susceptible to tumours?

Answer 24

Immunocompromised

Question 25

What cells are tumour specific antigens found on?

Answer 25

Antigens found on restricted tumour cells

Question 26

What cells are tumour associated antigens found on?

Answer 26

Antigens found on both normal and tumour cells | Tumour = overexpressed

Question 27

What can be used as a non-invasive way of diagnosing cancer, when they have been released into the bloodstream?

Answer 27

Tumour specific antigens | Tumour associated antigens

Question 28

Why are tumour associated antigens not good targets for therapeutic purposes?

Answer 28

On both normal and tumour cells

Question 29

What are the 4 ways tumour evade the immune system response?

Answer 29

Reduce expression of MHC Antigen masking - hide tumour associated/specific antigens Immunosuppression Tolerance

Question 30

What are the direct effects of malignant or benign tumours?

Answer 30

``` Obstruction Pressure Replacement of normal tissue (malignant) Dyshaematopoiesis Bone fracture Malabsorption Haemorrhage Infection ```

Question 31

Tumours can cause mural or extra mural obstruction. What do these mean? What does obstruction use?

Answer 31

Mural - against cavity wall Extra mural - outside cavity wall Disruption of arterial, venous and lymphatic flow

Question 32

Tumours can induce pressure on surrounding tissue. What might this cause the tissue to do if in a non-expandable cavity?

Answer 32

Atrophy

Question 33

How can tumours cause dyshaematopoiesis?

Answer 33

Invade myeloid tissue

Question 34

What are secondary tumours?

Answer 34

Tumours caused by metastasis from the original tumour location (primary tumour)

Question 35

How can tumours cause malabsorption?

Answer 35

If in gut wall, cause thickening which reduces absorption

Question 36

Tumours can cause haemorrhages. They can be chronic or acute. What are the results of these?

Answer 36

Acute - possibly fatal, hypovolaemic shock | Chronic - anaemia

Question 37

Why are secondary infections common with tumours?

Answer 37

Epithelial ulceration | Immunosuppression

Question 38

What are some indirect effects of tumours?

Answer 38

Paraneoplastic syndromes Hormonal effects Hypertrophic pulmonary oesteoarthropathy

Question 39

What is paraneoplastic syndrome?

Answer 39

Systemic complications caused by tumour cell products, not the tumour itself

Question 40

Do benign or malignant tumours alter hormones more as part of their indirect effect?

Answer 40

Benign - keep cell architecture (requires some differentiation)

Question 41

What is tumour cachexia (wasting syndrome)?

Answer 41

Loss of fat and muscle due to tumour | Causes anorexia or polyphagia

Question 42

How can tumour cells cause polyphagia/anorexia in tumour cachexia? (Wasting syndrome)

Answer 42

Tumour cells produce cytokines | Act on brain to cause change in appetite