Week 12

Question 1

how is the mortality of cancer changing over time

Answer 1

it is decreasing

Question 2

how is the incidence of cancer changing over time

Answer 2

it is not changing

Question 3

is cancer inherited

Answer 3

no, but certain inherited mutations can predispose one to cancer

Question 4

define: oncogenesis

Answer 4

process by which normal cells transform into cancerous cells

Question 5

how does cancer begin

Answer 5

loss of cell cycle control forming a tumour

Question 6

what are the 4 types of cancer

Answer 6

• carcinoma
• sarcoma
• leukemia
• lymphoma

Question 7

define: carcinoma

Answer 7

cancer of epithelial origin

Question 8

define: sarcoma

Answer 8

cancer of connective tissue

Question 9

define: leukemia

Answer 9

cancer of blood-forming tissue

Question 10

define: lymphoma

Answer 10

cancer of cells of the immune system

Question 11

what are examples of tumor suppressor genes

Answer 11

p53 and RB

Question 12

what is cyclin-dependent kinase (CDK) regulated by

Answer 12

cyclin

Question 13

what does the CDK regulated by cyclin D normally bind to

Answer 13

the start checkpoint

Question 14

what does p53 regulate in mammals

Answer 14

G1 to S checkpoint

Question 15

what is the function of p53

Answer 15

transcription factor that induces expression of p21

Question 16

what does p21 do

Answer 16

inactivates CDK, stops movement into S phase

Question 17

at what point does apoptosis occur in relation to p53

Answer 17

when p53 concentration increases to a certain level

Question 18

do mutations of p53 act dominantly or recessively

Answer 18

recessively

Question 19

what percentage of all cancers are associated with mutations in p53

Answer 19

~50%

Question 20

what does RB regulate

Answer 20

G1 to S checkpoint

Question 21

what is the function of the protein product RB

Answer 21

controls the cell cycle

Question 22

what happens in the absence of function RB

Answer 22

S phase cannot be stopped, results in uncontrolled cell growth

Question 23

how does inheritance play into retinoblastoma

Answer 23

inheritance of one copy of the RB allele predisposes individuals to cancer of the retina

Question 24

define: sporadic (in terms of retinoblastoma)

Answer 24

requires two independent mutations of RB to begin oncogenesis, child inherits normal alleles

Question 25

why is the RB mutation considered autosomal dominant

Answer 25

there exists a strong likelihood that another mutation in the normal allele will eventually occur

Question 26

define: oncogenes

Answer 26

mutant alleles that act dominantly to stimulate proliferation

Question 27

how do telomerase genes play into cancer

Answer 27

normally the shortening of telomeres prevents uncontrolled replication, but there are mutations in genes controlling telomerase expression

Question 27

how does cancer develop over time

Answer 27

thought to arise by successive mutations in a clone of proliferating cells

Question 27

what is an example of a DNA virus that carries oncogenes

Answer 27

human papilloma virus strains 16 and 18

Question 27

what percentage of cervical cancer is women is associated with HPV strains 16 and 18

Answer 27

> 90%

Question 28

do cancer cells show loss of cell-cell communication

Answer 28

yes, they don't stop even if they make contact with other cells

Question 29

what is autocrine stimulation

Answer 29

form of cell signalling in which a cell produces signalling molecules which bind to receptors on its own surface

Question 30

are gap junctions present in cancer cells

Answer 30

no

Question 31

define: metastasis

Answer 31

disruption of local tissue (basement membrane) and invasion into distant tissues

Question 32

define: angiogenesis

Answer 32

stimulate growth of blood capillaries