Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Radiation Biology > Hall 18 - Cancer Biology > Flashcards

Hall 18 - Cancer Biology Flashcards

(44 cards)

Start Studying
1
Q

What are proto-oncogenes?

A

Positive growth regulators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are four mechanisms of oncogene activation?

A
  1. Retroviral integration near proto-oncogene causes increased expression via viral promoter (LTR)
  2. Gain of function mutations in only one copy > dominant oncogene (ex, RAS)
  3. Gene amplification leading to increased DNA copy number and expression (ex, MYC)
  4. Chromosome translocation can place a proto-oncogene under control of a strong promoter or aberrant fused proteins (ex, BCR-ABL)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are tumor suppressor genes?

A

Negative growth regulators (in the same signaling networks as proto-oncogenes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Tumor suppressor phenotype is _______ at the cellular level but inherited between generations in an autosomal ______ fashion.

A

Recessive, dominant

*Two-hit hypothesis: lose one = increase cancer risk; lose second one = transformation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do sporadic cases of cancer from tumor suppressor loss happen?

A

Loss of heterozygosity
One copy lost, other chromosome suffers a deletion and replicates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the defective gene and inheritance pattern for retinoblastoma? What cancers do these people get?

A

RB1
Dominant
Retinoblastoma, sarcoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the defective gene and inheritance pattern for Li-Fraumeni? What cancers do these people get?

A

p53 (or CHK2)
Dominant
Breast, lung, brain, sarcoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the defective gene and inheritance pattern for familial Wilms tumor? What cancers do these people get?

A

WT1 or WT2
Dominant
Wilms tumor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the defective gene and inheritance pattern for neurofibromatosis 1? What cancers do these people get?

A

NF1
Dominant
Neurofibroma, MPNST, cafe au lait spots, Lisch iris nodules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the defective gene and inheritance pattern for neurofibromatosis 2? What cancers do these people get?

A

NF2
Dominant
Schwannoma, meningioma, ependymoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the defective gene and inheritance pattern for familial adenomatous polyposis (FAP)? What cancers do these people get?

A

APC
Dominant
Colon, stomach, small bowel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the defective gene and inheritance pattern for von Hippel Lindau? What cancers do these people get?

A

VHL
Dominant
Kidney, adrenal, hemangioblastomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the defective gene and inheritance pattern for familial gastric cancer? What cancers do these people get?

A

E-CAD
Dominant
Stomach, breast (lobular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the defective gene and inheritance pattern for Gorlin syndrome? What cancers do these people get?

A

PTCH
Dominant
Basal cell carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the defective gene and inheritance pattern for Cowden syndrome? What cancers do these people get?

A

PTEN
Dominant
Hamartomas, increased cancer risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the defective gene and inheritance pattern for multiple endocrine neoplasia? What cancers do these people get?

A

MEN1 and MEN2
Dominant
Pituitary, pancreatic, parathyroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the most critical cell cycle checkpoint?

A

G1 to S
Commits cell to mitosis
Controlled by Rb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 6 phenotypic hallmarks of cancer?

Study These Flashcards
A
  1. Uncontrolled proliferation
  2. Failure to respond to growth-restrictive signals
  3. Failure to undergo apoptosis
  4. Escaping senescence
  5. Angiogenesis
  6. Invasion and metastases
19
Q

What is required to evade apoptosis and senescence?

Study These Flashcards
A

Loss of tumor suppressors

20
Q

How do cancer cells survive crisis related to p53?

Study These Flashcards
A

Activate telomerase
Telomere shortening normally causes senescence via p53

21
Q

What is a key molecule involved in local invasion of tumor cells?

Study These Flashcards
A

Loss of E-cadherin (E-CAD)

22
Q

What results from loss of E-CAD, change in integrins, affinity switch from cell-cell to cell-matrix?

Study These Flashcards
A

Local invasion
*Epithelial to mesenchymal transition (EMT)

Promoted by Snail, Slug, Twist, Zeb1/2

23
Q

Defect in what DNA stability gene leads to ataxia telangiectasia? How is it inherited?

Study These Flashcards
A

ATM (DSB repair)
Recessive

24
Q

Defect in what DNA stability gene leads to ataxia telangiectasia-like disorder? How is it inherited?

Study These Flashcards
A

MRE11
Recessive

25
Defect in what DNA stability gene leads to Nijmegen breakage syndrome? How is it inherited?
NBS (part of MRE complex) Recessive
26
Defect in what DNA stability gene leads to hereditary breast cancer? How is it inherited?
BRCA1 or BRCA2 (HR repair) *Dominant
27
Defect in what DNA stability gene leads to Fanconi anemia? How is it inherited?
FANCD2 and FANC (associates with BRCA1/2) Recessive
28
Defect in what DNA stability gene leads to HNPCC/Lynch syndrome? How is it inherited?
MSH2, MSH6, MLH1, PMS1, PMS2 (mismatch repair) *Dominant
29
Defect in what DNA stability gene leads to Seckel syndrome? How is it inherited?
ATR (activated by ssDNA) Recessive
30
Defect in what DNA stability gene leads to Bloom syndrome? How is it inherited?
BLM (RecQ helicase that unwinds stalled DNA replication fork) Recessive
31
Defect in what DNA stability gene leads to Werner syndrome? How is it inherited?
WS (RecQ helicase + interacts with DNA-PKcs, Ku in NHEJ) Recessive
32
Defect in what DNA stability gene leads to Rothmund-Thomson syndrome? How is it inherited?
RECQL4 (RecQ helicase) Recessive
33
Defect in what DNA stability gene leads to xeroderma pigmentosum? How is it inherited?
XP (genome wide NER) Recessive
34
Defect in what DNA stability gene leads to Cockayne syndrome? How is it inherited?
CSA, CSB (transcription-coupled NER) Recessive
35
How does PI3K lead to cancer?
Phosphorylates PIP2 to PIP3 (reversed by PTEN) > docking site and recruits Akt > active phosphorylated Akt promotes protein synthesis and cell growth (mTORC1), cell cycle progression (activates MDM2, inhibits p21/27, Wee1, Chk1), and escapes apoptosis (activates IAPs, inhibits pro-apoptotic proteins) PI3K/Akt/mTOR pathway
36
How is Akt implicated in cancer?
PI3K phosphorylates PIP2 to PIP3 (reversed by PTEN) >> docking site and recruits Akt >> active phosphorylated Akt promotes protein synthesis and cell growth (mTORC1), cell cycle progression (activates MDM2, inhibits p21/27, Wee1, Chk1), and escapes apoptosis (activates IAPs, inhibits pro-apoptotic proteins) PI3K/Akt/mTOR pathway
37
How is EGFR activated?
Ligand binding It is a canonical RTK Recruits SOS to activate Ras-GTP (from inactive Ras-GDP)
38
What is the EGFR pathway and how does it lead to cancer?
EGFR binding by ligand > SOS activates Ras-GTP > Raf > MEK > MAPK (ERK) > increased cyclin-CDK activity and transcription of target genes promoting cell proliferation
39
What are activators of the Ras/Raf/MAPK pathway?
GPCRs, integrins, SRc family kinases Anything that shuts down Ras GTPase activity to hydrolyze GTP (ex, *NF1)
40
What are the PI3K/Akt/mTOR, JAK/STAT, and Ras/Raf/MAPK pathways all downstream of?
RTKs
41
What normally happens without Wnt ligand?
APC/Axin complex promotes ubiquitination of beta-catenin > proteosomal degradation Otherwise, Wnt can bind to Frizzled and eventually stabilize beta-catenin > translocates to nucleus and promotes gene transcription
42
When TGF-beta binds to type II receptor dimer and activates the pathway, what gets phosphorylated to effect transcription?
SMAD2/3 > SMAD4 goes to nucleus (SMAD6/7 are inhibitory)
43
What are the effects of the TGF-beta pathway?
Activated SMAD2/3/4>> gene transcription >> increased inflammation (pneumonitis) >> decreased growth of epithelial cells >> increased fibrosis
44
What pathway is stimulated by proinflammatory cytokines TNF-a and IL-1, binding of Toll-like receptors, and UV radiation?
NF-kB IKK complex >> phosphorylates IkB (also possibly by ATM) >> degradation >> free NF-kB >> gene transcription (pro-survival)

Radiation Biology (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions