Lecture 15: cancer 33

Question 1

Identified tumour suppressor genes:

Answer 1

• Rb
• P53
• WT-1
• Ptc
• BRCA-1
• APC

Question 2

Inherited cancer predisposition diseases

Answer 2

• Retinoblastoma
• Li Fraumeni
• Wilm’s tumour
• Gorlin’s syndrome
• Breast cancer
• Familial adenomatous polyposis coli (FAP)

Question 3

Oncogenes vs tumour suppressor genes: number of alleles mutated to exert effect

Answer 3

oncogenes: one

TSG: 2

Question 4

Oncogenes vs tumour suppressor genes: effect on the function of the protein

Answer 4

oncogene: Enhanced

TSG: reduced

Question 5

Oncogenes vs tumour suppressor genes: inherited mutations:

Answer 5

oncogenes: RET, Abl

TSG: p53, RB, WT-1, Ptc, APC

Question 6

Oncogenes:

Answer 6

activate, gain of function, dominant

Question 7

TSG:

Answer 7

inactivating, loss of function, recessive

Question 8

normal cell division, normal apoptosis:

Answer 8

HOMEOSTASIS

Question 9

INCREASED cell division, normal apoptosis :

Answer 9

TUMOUR

Question 10

Normal cell division, DECREASED apoptosis :

Answer 10

TUMOUR

Question 11

cell cycle

Answer 11

G1 - growth 1
S - replicate genome
G2 - growth phase 2
M - cell division

Question 12

Many genes control cell division:

Answer 12

• Many Genes Promote Cell Division

- Many Genes Block Cell Division

Question 13

DNA detected by stable, active p53

Answer 13

• Hyperproliferative signals
• DNA damage
• Telomere shortening
• Hypoxia

Question 14

outcome from p53 detecting DNA damage

Answer 14

• cell cycle arrest
• senescence
• apoptosis

Question 15

p53 has been called the

Answer 15

‘guardian of the genome’

Question 16

p53

Answer 16

• arrests cells when DNA is damaged

• turns on transcription of DNA repair genes and
genes that arrest cell cycle

• turns on apoptosis when all else fails

Question 17

many cancers arise from defects in the machinery that regulates

Answer 17

cell growth and/or cell death

Question 18

most cancer cells are defective in apoptotic response
⇑anti-apoptotic or
⇓ pro-apoptotic proteins

Answer 18

CANCER

Question 19

Cancer cells have tricks to avoid apoptosis:

B-cell leukemias and lymphomas express

Answer 19

high levels of Bcl-2

Question 20

Cancer cells have tricks to avoid apoptosis: Lung and colon cancer cells
secrete

Answer 20

“decoy” molecules that bind and inactivate MHC type1 receptors

⇓T cell recognition sites
—Cytotoxic T-lymphocytes & NK cannot kill the cancer cells

Question 21

routes of tumour spread

Answer 21

• direct
• via lymphatics
• transcoelomic
• field change
• via bloodtsream

Question 22

Metastasis mechanism

Answer 22

still poorly understood

Question 23

metastasis is promoted by

Answer 23

• ⇓ adherence between cells
• Synthesis of defective basement membrane
• Tumour angiogenesis
• ⇑cell motility
• Secrete growth factors
• Secrete alternative extracellular matrix
• Secrete proteinases
• Evade host immune system

Question 24

treatment for cancer:

Answer 24

• Surgery
• Radiotherapy
• -Chemotherapy
• Endocrine-related treatments
• Immunotherapy
• –Interferons, vaccination
• Molecular mechanism-based

Question 25

an effective screening should be

Answer 25

-Be affordable to the healthcare system --Be acceptable to all social groups -Have good discrimination between benign & malignant lesions -Show a reduction in mortality from the cancer

Question 26

Herceptin as mode of action

Answer 26

=monoclonal antibody binds to erbB2 receptor sites Inhibits receptor function 1.Cell cycle arrest blocks cell cycle in G1 2. Suppresses angiogenesis ⇑antiangiogenic factors ⇓proangiogenic factors

Question 27

cancer is a ___ of diseases

Answer 27

group

Question 28

cancer is controlled / uncontrolled cell division

Answer 28

uncontrolled | - aberrant differentiation & cell interactions

Question 29

2 types of tumours:

Answer 29

benign & malignant

Question 30

cancer affects

Answer 30

a large proportion of the population (but is rare from the cells perspective)

Question 31

Many carcinogens act as

Answer 31

mutagens - cancer not usually become apparent until years after exposure

Question 32

_____ in cellular function need to occur before a cell can become malignant

Answer 32

MULTIPLE CHANGEs include defects in the machinery that regulates cell growth and death

Question 33

Gain of function mutations occur in

Answer 33

oncogenes

Question 34

loss of function mutations associated with

Answer 34

tumour suppressors

Question 35

many cancers display

Answer 35

genomic instability

Question 36

cancer may arise from

Answer 36

'stem cells'

Question 37

__ treatments are availble

Answer 37

variable - often used in combination

Question 38

New insights into tumour biology is providing

Answer 38

new therapies