Week 4 - Cancer Biology

Question 1

What is another name for a tumour

Answer 1

Neoplasm

Question 2

Describe the growth of a benign tumour

Answer 2

Grows slowly and remains located to the site of origin

Question 3

Describe the growth of a malignant tumour

Answer 3

They grow fast, invade and spread to different sites

Question 4

Metastasis

Answer 4

A multistep process by which tumour cells move form a p to a s site

Question 5

How does cancer cell morphology differ in cancer cells

Answer 5

They have large, variably shaped nuclei

Many dividing cells

Variation in size and shape

Loss of normal features

Question 6

6 characteristics of cancer

Answer 6

Self-sufficiency in growth signals

Insensitivity to growth-inhibitory signals (inactivation of tumour suppressor genes)

Evasion of programmed cell death

Limited replication potential

Sustained angiogenesis (can draw blood supply)

Tissue invasion and metastasis

Question 7

What are CDKs

Answer 7

enzymes

Question 8

Cells receive which signal to enter the cell cycle

Answer 8

Growth factors

Question 9

What is an oncogene

Answer 9

A gene who’s product in involved in inducing cancer

Question 10

What is a proto-oncogene

Answer 10

A normal cellular gene that encodes a protein usually involved in regulation of cell growth/differentiation WHEN MUTATED causes ONCOGENE

Question 11

Which two main factors cause formation of a tumour

Answer 11

Molecules that aree initiate/speed up proliferation are switched on

Molecules that slow down proliferation are switched off

Question 12

Examples of receptors that when switched on, initiate/speed up proliferation

Answer 12

EGFR
HER2
c-Met

Question 13

Examples of cytoplasmic signalling intermediates (transducers) when switched on, initiate/speed

Answer 13

Ras
BRAF
Abl, Src (kinases)

Question 14

Examples of nuclear molecules when initiated/switched speed proliferation

Answer 14

Cyclin D
Myc (transcription factor)
Fos, Jun

Question 15

Are mutations that cause molecules to initiate/speed up proliferation dominant or recessive

Answer 15

Dominant

Question 16

What can proto-oncogene RAS cause

Answer 16

RAS -
NORMALLY
produces G protein that transduces signals from cell surface receptors

WHEN POINT MUTATION
‘Ras’ that is always on - repeated stimulation

e.g 30% of tumours

Question 17

What can proto-oncogene BRAF cause

Answer 17

NORMALLY
produces kinase that transduces signals from cell surface receptors

WHEN POINT MUTATION
Hyperactive kinase activity that is ‘on’ all the time

e.g >50% of all melanomas

Question 18

What can proto-oncogene EGFR cause

Answer 18

NORMALLY
produces a cell surface receptor that receives an extracellular signal

WHEN DELETION MUTATION
receptor is activated in absence of EGF

e.g non-small cell lung cancer

Question 19

What can ERB B2 (HER2) proto-oncogene cause

Answer 19

NORMALLY
Produces HER2

WHEN GENE AMPLIFICATION
More receptors equalling more stimulation

Question 20

What can proto-oncogenes BCR + ABL cause

Answer 20

Philadelphia translation causing bcr-abl hybrid gene - causing persistent activated kinase activity

Found in CML

Question 21

2 examples of cancers caused by Rb protein mutations

Answer 21

Retinoblastoma
Breast cancer

Question 22

2 examples of mutated p53 protein cancers

Answer 22

Brain tumours
Leukaemia

Question 23

Rb tumour supressor- dominant or recessive?

Answer 23

Recessive- two copies of mutated genes required for a cell to become cancerous

(germline + somatic)

Question 24

p53 tumour supressor - dominant or recessive?

Answer 24

Dominant negative

Question 25

What is the role of BCL-2

Answer 25

B-cell lymphoma-2 regulates apoptosis

Question 26

What is different about the BCL-2 gene of cancer cells

Answer 26

They have undergone a translocation mutation, causing increased expression of pro-survival BCL-2 proteins

Question 27

What do telomerase enzymes do

Answer 27

They add telomeres on which protect chromosome ends

Question 28

In cancer cells, what is different about telomerase enzymes

Answer 28

They express more telemorases which prevents chromosomes from shortening and results in limitless replicative potential

Question 29

What is angiogenesis

Answer 29

When tumour grows, cells further away from blood vessels receive insufficient nutrition and become hypoxic. This stimulates tumour cells to produce VEGF (vascular endothelial growth factor) which causes vessels to grow towards the tumour

Question 30

What happens to the tight junctions of epithelial tumours

Answer 30

They lose epithelial-cadherin which form part of the adherens junction

Question 31

Metastasis is aided by which group of 23 enzymes and what is their function

Answer 31

Matrix metalloproteinases (MMPs)

They use these specific enzymes to break through structures such as the basement membrane, which gives cancer cells easier access to blood vessels

Question 32

What does Herceptin target

Answer 32

ERBB2 gene (causes b cancer)

Question 33

What does Bevacizumab target

Answer 33

VEGF gene (colorectal cancer)

Question 34

Which gene does imatinib target

Answer 34

ABL (CML)

Question 35

Venmurafenib targets?

Answer 35

BRAF (melanoma)