15. Cancer Genetics

Question 0

most deadliest form of cancer?

Answer 0

lung disease

Question 1

underlying cause of chronic disease?

Answer 1

inflammation

obesity is an inflammatory disease

Question 2

type of cancer with most number of new cases?

Answer 2

prostate & breast

Question 3

oncogene

Answer 3

mutated or over-expressed gene that causes cancer

Question 4

proto-oncogene

Answer 4

normal gene which can become an oncogene if adequately mutated

Question 5

gain-of-function mutation

Answer 5

mutation that results in a new molecular function or pattern of expression

take normal cellular genes (proto-oncogenes) & turn them into oncogenes

Question 6

loss-of-function mutation

Answer 6

mutations that inactivate or decrease the activity of a gene

Question 7

cell transformation

Answer 7

(malignant transformation)

Question 8

germline mutation

Answer 8

heritable mutation in germline cells

all cells of the offspring will be affected by this mutation

Question 9

somatic mutation

Answer 9

mutations that occur in cells of the body EXCEPT germline cells

mutations will be passed on to cell progeny but not offspring of the organism

Question 10

driver mutation

Answer 10

mutations that cause a proto-oncogene to become an oncogene

confer a growth advantage in the cancer cell

Question 11

passenger mutation

Answer 11

mutation present in the cancer genome that did not contribute to the transformation of the proto-oncogene to an oncogene

did not confer a growth advantage on the cancer cell

mutations “along for the ride”

Question 12

complete penetrance

Answer 12

100% of individuals who have a malignant mutation/oncogene express the phenotype

Question 13

incomplete/reduced penetrance

Answer 13

less than 100% of individuals who have a malignant mutation/oncogene express the phenotypes of the disease

Question 14

expressivity

Answer 14

the severity (varying levels) at which an individual expresses the phenotype of a malignantly mutated gene

Question 15

cause of most cancers?

Answer 15

normal cellular genes (proto-oncogenes) which have been transformed into an oncogene

Question 16

gain of function mutations

Answer 16

proto-oncogene is transformed into an oncogene

usually dominant mutation

results in overexpression of that gene (or inability to turn off)

Question 17

loss of function mutations

Answer 17

leads to cell transformation
more rare
usually recessive mutation

Question 18

ways that a proto-oncogene could become an oncogene?

Answer 18

some kind of point mutation in transmembrane domain of a receptor that causes it to be permanently active

mutation of GTPase in G protein

Mek (immediate early gene used for driving expression of genes involved in growth & mitogenesis)

mutation in ras that makes it seem like GEF is constantly bound to it (constantly active)

an enhancer insertion mutation (enhancer inserted before the gene, causing its overexpression)

Question 19

what do most oncogenes code for? (4 things)

Answer 19

1. growth factors
2. growth factor receptors
3. intracellular signal transducers
4. nuclear transcription factors

Question 20

oncogene activation of the ERK MAPK cascade

Answer 20

mutation in ERK MAPK cascade could cause cancer because of the cascades effect on nuclear transcription, especially with mutations in ras or raf

Question 21

germline mutations

Answer 21

heritable, occur in the germline cells of the organism & will be passed on to their offspring

can cause cancer family syndromes

Question 22

driver mutations

Answer 22

mutations that cause transformation of a proto-oncogene into an oncogene

confer a growth advantage on the cancer cell

accumulation of these mutations leads to an oncogene

Question 23

passenger mutations

Answer 23

“along for the ride”

random, accumulated mutations that are present on the final genome of the cancer cell but did not contribute to the cell becoming cancerous

Question 24

warburg effect

Answer 24

cancer cells grow via preference for anaerobic metabolism (glycolysis) & outcompeting of neighboring cells for glucose uptake

marginalization of MT (MT controls apoptosis, so marginalization of MT helps cancer cell avoid programmed cell death)

Question 25

penetrance

Answer 25

all or nothing

characterizes the frequency of an oncogene’s phenotypical expression

Question 26

complete penetrance

Answer 26

100% of individuals who have the oncogene express the phenotypes of the disease

usually autosomal recessive

Question 27

incomplete penetrance

Answer 27

phenotype expression is less than 100%

usually autosomal dominant

Question 28

risk factors associated with prevalence?

Answer 28

environmental factors

age

Question 29

expressivity

Answer 29

severity of expression of the phenotype among individuals with the same disease-causing genotype

ex. neurofibromatosis

Question 30

two hit hypothesis

Answer 30

you need multiple mutations for cancer to result (need more than 1 mutation for cancer)

“first hit” = germline mutation
“second hit” = somatic mutation