Neoplasia 3 Flashcards

0
Q

How do infections induce neoplasms indirectly?

A
  • Chronic tissue injury and regeneration -> mutations
  • Reduced immunity e.g. HIV
  • Helicobacter pylori
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1
Q

How do infections induce neoplasms directly?

A
  • Directly: affects genes controlling cell growth
  • HPV: E6 inhibits p53 (reparative/apoptosis)
    E7 inhibits pR6 (cell proliferation)
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2
Q

What link is there between chemicals neoplasms?

A
  • Long delay between carcinogen exposure and malignant neoplasm onset
  • Risk depends on carcinogen dosage
  • Sometimes organ specific
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3
Q

What is meant by a complex carcinogen?

A
  • It is both an initiator and promoter

- Smoking

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4
Q

What sources of radiation are commonly the cause of some neoplasms?

A
  • Radon gas
  • Medical tests
  • UV light
  • Free radical damage
  • Ionising radiation: radioactive (a,b,y)
    electromagnetic (y,X,UV)
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5
Q

What types of damage can radiation cause?

A
  • Indirect damage: free radicals

- Direct DNA damage: altered bases, single/double stranded DNA breaks

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6
Q

Why is someone more likely to obtain cancer if they have a family history?

A
  • First hit is inherited via germ line
  • Affects all cells in the body
  • Easier to obtain cancer with germline mutation already present
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7
Q

What roles do RAS and RB genes have in neoplasia?

A
  • RAS encodes for a small G protein
  • This pushes cells past cell cycle restriction point
  • Mutation causes this to be constant
  • RB restricts cell passage through restriction point
  • Mutation = no control
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8
Q

What are the 6 main hallmark cellular behaviours?

A
  • Self sufficient growth signals
  • Resistance to anti-growth signals
  • Grows indefinitely
  • Induces new blood vessels
  • Apoptosis resistance
  • Invades and produces metastasise
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9
Q

What do Proto-oncogenes do and what happens to them in neoplasia?

A
  • Encode growth factors and receptors
  • Plasma membrane signal transducers
  • Intracellular kinases
  • Transcription factors
  • Only one of the POG alleles need to be activated for neoplastic growth
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10
Q

What do tumour-suppressor genes do and how are they affected in neoplastic growth?

A
  • TSG supply anti growth factor effects

- Needs both alleles to be inactivated hence 2 hit theory

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11
Q

Outline the adenoma to carcinoma sequence

A
  • Normal epithelium -> early adenoma -> intermediate adenoma -> late adenoma -> carcinoma -> metastasis
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