Outline of Cancer Disease Process Flashcards Preview

Principles of Disease 16 > Outline of Cancer Disease Process > Flashcards

Flashcards in Outline of Cancer Disease Process Deck (25)
1

Define cancer

Carcinoma or disorderly growth of epithelial cells which invade adjacent tissue and spread by the lymphatics and blood vessels to other parts of the body

2

What type of cells does cancer usually arise from?

Epithelial, only 20% arise from non-epithelial connective tissue, musculoskeletal or nervous tissues

3

How can you differentiate between normal and cancerous cells using a microscope?

• Lots of blood vessels (increased angiogenesis)
• Cells at different stages of the cell cycle
• Abnormal heterogeneous cells
• Irregular and messy borders
• Irregular nuclei

4

Describe the three stages of carcinogenesis

o Initiation – irreversible genetic damage to cells that proliferate and survive for the lifetime of the organism
o Promotion – reversible changes that increase chances of it progressing to cancer, including the selective clonal expansion of the initiated cells. This is aided by growth factors and oncogenes
o Progression – irreversible malignant conversion of the initiated prenoeplastic cell into one that expresses the malignant phenotype

5

How large does a tumour have to be before it is usually detected?

1cm

6

What can initiate carcinogenesis?

o Chemical carcinogens
o Physical carcinogens
o Viral carcinogens

7

Describe some chemical carcinogens that can initiate cancer development

Chemical carcinogens:
• Polycyclic hydrocarbons and soot on scrotal cancer
• Anilene dyes and bladder cancer
• Aflatoxin (mouldy peanuts) and liver cancer
• Nitrogen mustard and leukaemia
• Alcohol and smoking

8

Describe some physical carcinogens

Physical carcinogens:
• Ionising radiation – dose response relationship, affects chromosome translocation, influences gene amplification and activated oncogenes

9

Describe some viral carcinogens

Viral carcinogens:
• Herpes virus and Burkitts lymphoma
• Human papillomavirus and cervical cancer
• Retroviruses HTLV1 and HTLV2 on leukaemia + lymphoma
• Hepatitis B and liver cancer

10

What causes cancer promotion?

Mutations in either
- protoonocogenes e.g. Bcl2 activation
- growth factors
- tumour suppressor genes e.g. p53

11

What is Bcl2?

Bcl2 is a protooncogene, activation prevents apoptosis

12

What is p53?

Tumour suppressor gene, is the most commonly altered gene in human tumours (37% but higher in lung and colon).

13

What is the normal function of tumour suppressor genes?

Normal function is as transcriptional regulator; promotes DNA repair, apoptosis, differentiation

14

What usually causes genetic mutations?

DNA damage and hypoxia

15

What enzymes allow the spread of cancer into the ECM?

• Matrix metalloproteinases (MMPs)
• Plasmin
• Cathepsin

16

What cell adhesion molecules are affected during invasion by tumour cells?

• Cadherins
• Integrins
• CD44

17

What type of imaging is particularly useful when testing for metastases?

PET

18

How big can a tumour get without the requirement of angiogenesis?

2mm

19

What is Avastin (bevacizumab)?

• The humanised anti-VEGF MAb Avastin (bevacizumab) prevents the interaction of VEGF with its receptors, VEGF receptor-1 and VEGF receptor-2 on the surface of vascular endothelial cells.
• This prevents activation of the VEGF receptors and of the downstream signalling pathways that would normally lead to the growth, proliferation, migration and survival of endothelial cells of the blood vessels.

20

What is PDL1?

• Programmed death-ligand 1 (PD-L1) is a 40kDa type 1 transmembrane protein that has been speculated to play a major role in suppressing the immune system during particular events such as pregnancy, tissue allografts, autoimmune disease and other disease states such as hepatitis.
• PDL-1 has now been found to be expressed on some tumour cells

21

What drug targets PDL1?

atezolizumab

22

What is atezolizumab?

PDL1 MAb

23

What is ipilimumab?

Ipilimumab is a monoclonal antibody that works to activate the immune system by targeting CTLA-4, a protein receptor that downregulates the immune system.

24

What drug targets CTLA4?

Ipilimumab

25

What immune checkpoints are targeted in cancer treatment?

CTLA4 - suppresses immune response
PDL1 - suppresses immune response