Brainscape's Knowledge GenomeTM

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


See full index

MoD > L20 - Carcinogenesis - causes of cancer > Flashcards

L20 - Carcinogenesis - causes of cancer Flashcards

1
Q

Give some examples of occupational carcinogens

A
  • cadmium and nickel
  • radon (mining)
  • solvents and preservatives (painters and furniture makers)
  • tannins (leather footwear manufacture)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Give examples of chemical carcinogens

A
  • PAHs

- nitrosamines

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

Give examples of infectious agents as carcinogens

A
  • HPV

- H. pylori

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

Give examples of radiation as a carcinogen

A
  • UV light

- radon

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

Give examples of mineral carcinogens

A
  • asbestos

- heavy metals

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

Give examples of physiological carcinogens

A
  • oestrogen

- androgens

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

What are the carcinogens involved in chronic inflammation?

A
  • free radicals

- growth factors

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

Which organ does aflatoxin target?

A

Liver

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

Which organs does alcohol target?

A

Pharynx, larynx, oesophagus, liver

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

Which organ does asbestos target?

A

Lung pleura

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

Which organ do X-rays target?

A

Bone marrow (leukaemia)

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

Which organ does UV light target?

A

The skin

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

Which organ does oestrogen target?

A

Breast

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

Which organs does tobacco smoke target?

A

Mouth, lung, oesophagus, pancreas, kidney, bladder etc

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

Which organ does HBV (hepatitis B virus) target?

A

Liver

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

Which organ does HPV (human papilloma virus) target?

A

Cervix

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

Carcinogen can also be non-genotoxic. What does this mean?

A

Induce proliferation and DNA replication

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

What is an INITIATOR?

A

A carcinogen that can modify or damage DNA (genotoxic)

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

What is a PROMOTER

A

A carcinogen that can induce proliferation and DNA replication (non-genotoxic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a “complete” carcinogen?

A

A carcinogen that can both initiate and promote.

eg. UV light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does mutation induction (initiation) require?

A
  • chemical modification of DNA

- replication of modified DNA and mis-incorporation by DNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How might chemical modification of the nucleotides involved in base-pairing occur?

A

Through environmental insult or through the action of endogenous reactive molecules such as free radicals produced by normal physiological processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Agents that are good promoters contribute to carcinogenesis in 2 important ways. What are they?

A
  • stimulate the 2 rounds of DNA replication

- stimulate clonal expansion of mutated cells, enabling the accumulation of mutations

24
Q

Give some common genetic abnormalities

A
  • base pair substitution
  • frameshift
  • deletion
  • gene amplification
  • chromosomal translocation
  • chromosomal inversion
  • aneuploidy
25
Q

What is a base pair substitution also known as?

A

Point mutation

26
Q

What is a frameshift mutation?

A

Gain or loss of one to several base pairs

27
Q

What can gene amplification result in?

A

A cell having up to a hundred copies of a gene that would normally only have two copies of

28
Q

Chr 9:22 exchange is a specific translocation. What is it known as and what is it associated with?

A

Philadelphia chromosome

Associated with chronic myeloid leukaemia

29
Q

Chromosomal translocations can result in what?

A
  • genes being moved to a more transcriptionally active region of the chromosome
  • genes being recombined into new gene fusions
30
Q

What is aneuploidy?

A

Any departure from the normal structure or number of chromosomes

31
Q

Mutations found in oncogenes lead to what?

Mutations found in TSGs lead to what?

A

Mutations found in oncogenes lead to a gain in function

Mutations found in TSGs lead to a loss of function

32
Q

What are direct acting carcinogens?

A

Interact directly with DNA

eg. oxygen radicals, nitrosamines, UV light, ionising radiation

33
Q

What are procarcinogens?

A

Require enzymatic (metabolic) activation before they react with DNA

eg. aromatic amines, polycyclic aromatic hydrocarbons (PAHs)

34
Q

Are the majority of carcinogens that we ingest direct acting or procarcinogens?

A

The majority are pro carcinogens and require metabolic activation by enzymes that normally function in the detoxification and excretion of toxic chemicals

35
Q

What are the products in the metabolic activation of benzopyrene?

A

Benzopyrene

Benzopyrene 7,8-epoxide

Benzopyrene 7,8-dihydrodiol

Benzypyrene 7,8-diol, 9,10-epoxide

Ultimate carcinogen = BPDE

36
Q

What are the enzymes involved int he activation of benzopyrene?

A

P450 mixed function oxidases

Epoxide hydrolase

P450 mixed function oxidases

37
Q

Give a classic example of a procarcinogen and state how it can be generated

A

Benzopyrene

Can be generated through the combustion of most organic material such as meat, tobacco and fuel

38
Q

BPDE causes mutation in which gene?

A

TP53

seen in this gene in the lung tumours of smokers

39
Q

What are the 4 general stages in DNA damage and repair?

A
  1. Damaging agent
  2. DNA lesions
  3. Repair process
  4. Disease syndrome
40
Q

Give a pathway from carcinogen exposure to cancer

A
  • carcinogen exposure
  • metabolic activation (eg. cytochrome P450s)
  • DNA damage
    (- DNA repair)
  • DNA replication
  • DNA mutation (eg. in proto-oncogene or tumour supressor gene)
  • progression
  • cancer
41
Q

At which stages of the pathway from carcinogen exposure to cancer may genetic modulation occur?

A
  • metabolic activation
  • detoxification and excretion
  • DNA repair

(may explain why exposure does not always lead to cancer)

42
Q

Which cancers is alcohol linked to?

A 
Oral
Oesophageal
Pharynx
Larynx
Breast
Bowel
Liver
(Pancreatic)
43
Q

What is alcohol converted into that can cause DNA damage?

A

Acetaldehyde

44
Q

Alcohol increases levels of which hormones?

A

Oestrogen and testosterone

45
Q

Alcohol increases the uptake of what?

A

Carcinogenic chemicals into cells within the upper GI

46
Q

Alcohol reduces levels of what?

A

Folate, needed for accurate DNA replication

47
Q

Alcohol can kill what?

A

Surface epithelium leading to unscheduled proliferation

48
Q

All of the strongest risk factors for breast cancer are associated with what?

A

Increased exposure to oestrogen - can both stimulate cell division and induce DNA damage

49
Q

Breast cancer risk decreases 20% for what?

A

Risk decreases 20% for each year that menarche is delayed

50
Q

What procedure leads to 90% decrease in risk of breast cancer?

A

Oopherectomy

removal of ovaries

51
Q

What procedure reduces incidence of prostate cancer?

A

Orchidectomy

removal of a testis

52
Q

Which types of chronic inflammation have an association with cancer?

A
  • colitis
  • hepatitis
  • Barret’s oesophagus
  • metaplasia
  • gastritis
  • gallstones
53
Q

Inflammatory response results in a ‘double whammy’. What does this mean?

A
  • DNA damage from release of free radicals by immune cells - initiation
  • growth factor induced cell division to repair tissue damage - promotion
54
Q

Which cell is key in the link between inflammation and cancer?

A

Tumour-associated macrophages (TAMs)

55
Q

what 2 consequences can mutations have?

A
  • gain of function (activation of proto-oncogenes)

- loss of function (inactivation of tumour suppressor genes)

56
Q

what defence does the human body have against carcinogenesis?

A
  • Dietary antioxidants
  • Detoxification mechanisms [by enzymes]
  • DNA repair enzymes
  • Apoptotic
    response to unrepaired genetic damage
  • Immune response

MoD (19 decks)

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