Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 2-PP > Session 9-Neoplasia 3 > Flashcards

Session 9-Neoplasia 3 Flashcards

1
Q

Define carcinogenesis

A

Causes of cancer

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

Which intrinsic and extrinsic factors account for cancer risk?

A

Intrinsic host factors-age, sex heredity

Extrinsic-environment, lifestyle

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

What are the three main categories of extrinsic carcinogens?

A

Chemicals
Radiation
Infections

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

What is an industrial carcinogen used in the dye manufacturing industry?

A

2-napthylamine

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

What did malignant neoplasms caused by 2-napthylamine show?

A

1) long delay between carcinogen exposure and malignant neoplasm onset
2) risk of cancer depends on total carcinogen dosage
3) there is sometimes organ specificity for particular carcinogens

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

True or false: promoters must be administered before initiators to cause cancer

A

FALSE - other way round

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

What does the Ames test show?

A

That initiators are mutagens while promotors cause prolonged proliferation in target tissues

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

What can mutagenic chemical carcinogens be classified as?

A 
Polycyclic aromatic hydrocarbons
Aromatic amines
N-nitroso compounds 
Alkylating agents
Diverse natural products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are pro-carcinogens?

A

Mutagenic chemicals which are only converted to carcinogens by cytochrome P450 enzymes in liver

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

What are complete carcinogens?

A

Carcinogens that act as both initiators and promoters

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

True or false: UV light doesn’t penetrate deeper than skin

A

TRUE

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

What is ionising radiation and what are some examples?

A

Strips electrons from atoms

X-rays and nuclear radiation from radioactive elements

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

What does nuclear radiation comprise of?

A

Alpha particles, beta particles and gamma rays

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

How can radiation damage DNA indirectly?

A

Generates free radicals

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

How does ionising radiation damage DNA directly?

A

Ionising radiation damages DNA bases and causes single and double strand DNA breaks

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

What is the most important type of radiation and why?

A

UV because we are exposed daily from sunlight leading to increased skin cancer risk

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

What is the main exposure to ionising radiation?

A

Natural background radiation from radon which seeps from earth’s crust

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

How are some infections indirectly carcinogenic?

A

Affect genes that control cell growth indirectly by causing chronic tissue injury where the resulting regeneration acts as promoter for any pre-existing mutations or else causes new mutations from DNA replication errors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is human papilloma virus (HPV) a direct carcinogen?

A

Expresses E6 and E7 proteins that inhibit p53 and pRB protein function respectively, both of which are important in cell proliferation

20
Q

True or false: hep B and C viruses are indirect carcinogens that cause chronic liver cell injury and regeneration

A

TRUE

21
Q

Complete the sentence:

Helicobacter pylori causes chronic __________ inflammation and parasitic flukes cause inflammation in _____ ______ and __________ mucosa, increasing risk of _________, cholangio- and _________ carcinomas respectively.

A 
Gastric
Bile ducts
Bladder
Gastric 
Bladder
22
Q

How is HIV carcinogenic?

A

Indirectly - lowers immunity and allows other potentially carcinogenic infections to occur (eg Kaposi sarcoma)

23
Q

How can inherited predisposition to neoplasia occur?

A

Through germline mutations

24
Q

How does initiation and promotion lead to neoplasms?

A

When they affect proto-oncogenes and tumour suppressor genes

25
Q

Why do tumour suppressor genes need two hits?

A

One for each allele as both alleles need to be inactivated

26
Q

True or false: only one allele of each proto-oncogene needs to be activated to favour neoplastic growth

A

TRUE

27
Q

What was the first human oncogene to be discovered?

A

RAS

28
Q

What does the RAS proto-oncogene encode?

A

Small G protein that relays signals into cell that eventually pushes cell past cell cycle restriction point

29
Q

What does mutant RAS encode?

A

Protein that is always active, ultimately producing constant signal to pass through cell cycle’s restriction point

30
Q

How does the RB gene (retinoblastoma) restrain cell proliferation and what does inactivation of both RB alleles allow?

A

Inhibits passage through restriction point

Inactivation of both alleles allows unrestrained passage through restriction point

31
Q

How can the restriction point be deregulated?

A

By combination of activated oncogene and inactivated tumour suppressor gene

32
Q

What can proto-oncogenes encode?

A
  • growth factors (eg PDGF)
  • growth factor receptors (eg HER2)
  • plasma membrane signal transducers (eg RAS)
  • intracellular kinases (eg BRAF)
  • transcription factors (eg MYC)
  • cell cycle regulators (eg CYCLIN D1)
  • apoptosis regulators (eg BCL2)
33
Q

What do tumour suppressor genes encode?

A

Proteins in the same pathways as proto-oncogenes but with anti-growth effects

34
Q

What is xeroderma pigmentosum (XP) due to?

A

Mutations in DNA repair genes

35
Q

True or false: xeroderma pigmentosum is autosomal dominant

A

FALSE - recessive

36
Q

What is XP due to?

A

Mutations in one of 7 genes that affect DNA nucleotide excision repair

37
Q

What are patients with XP sensitive to and what does this lead to?

A

UV damage and can lead to skin cancer at young age

38
Q

What is hereditary non-polyposis colon cancer (HNPCC) syndrome associated with and what does the mutation affect?

A

Colon carcinoma and germline mutation affects one of several DNA mismatch repair genes

39
Q

True or false: hereditary non-polyposis colon cancer (HNPCC) syndrome is autosomal dominant

A

TRUE

40
Q

What is familial breast carcinoma associated with and what can mutations of these be found in?

A

BRCA1 and BRCA2 genes - important for repairing double strand DNA breaks

Various mutations can also be found in sporadic malignant neoplasms

41
Q

What is genetic instability?

A

Abnormal chromosome segregation during mitosis , together with mutations in DNA repair genes accounts for accelerated mutation rate in malignant neoplasms = genetic instability

42
Q

What are caretaker genes?

A

Genes that maintain genetic stability (class of tumour suppressor genes)

43
Q

What is the adenoma-carcinoma sequence?

A

Colon carcinoma usually starts as colonic adenoma and then progresses to carcinoma

44
Q

What is cancer progression?

A

Steady accumulation of multiple mutations

45
Q

How many mutations are needed to make a malignant neoplasm?

A

10 or less

46
Q

What are the six hallmarks of cancer exhibited by malignant neoplasms?

A

1) self-sufficiency in growth signals
2) resistance to growth stop signals
3) no limit on number of times a cell can divide (cell immortalisation)
4) sustained ability to induce new blood vessels (angiogenesis)
5) resistance to apoptosis
6) ability to invade and produce metastases

Semester 2-PP (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions