Oncology 4 Flashcards

1
Q

What are the 6 hallmarks of cancer?

A
  • self-sufficiency in growth signals
  • insensitivity to anti-growth signals
  • evasion of apoptosis
  • sustained angiogenesis
  • tissue invasion and metastasis
  • limitless reproductive potential
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2
Q

In normal cells, growth and division requires external ____s

A

growth factors

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3
Q

Growth factors are produced by ______ and bind to ______

A
  • other cells

- cell receptors

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4
Q

What do growth factors trigger? What does this in turn trigger?

A

Growth factors trigger intracellular kinases

These trigger cell division

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5
Q

What is an important characteristic of growth factors regarding chemical composition?

A

They are diffusible

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6
Q

When does abnormality of growth occur with cancer cells?

A
  • too many receptors and overstimulation of growth

- self-production and release of GFs (stimulate growth)

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7
Q

What type of trigger causes abnormality of growth in cancer cells?

A

may be genetic or environmental

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8
Q

What are oncogenes?

A
  • small segments of DNA

- can transform normal cells into malignant ones

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9
Q

Where do oncogenes come from?

A

Activated from “normal” proto-oncogenes by a mutation

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10
Q

What signals a cell to stop reproduction?

A

anti-growth signals from other cells

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11
Q

What are the anti-growth signals used by other cells to signal a stop in reproduction?

A
  • soluble growth factors
  • immobilized inhibitors embedded in the extracellular matrix
  • immobilized inhibitors on the surfaces of nearby cells
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12
Q

What causes cells to become insensitive to anti-growth signals?

A
  • stop listening to normal cells

- keep dividing over normal cells that have stopped growing

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13
Q

Anti-growth signals are associated with this point in the cell cycle?

A

G1 checkpoint

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14
Q

How do nectins and nectin-like substances play a role in normal cells?

A
  • contact inhibition

- limiting movement of cells

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15
Q

What is contact inhibition?

A

Mitosis is prevented once cells of a tissue come in contact with one another

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16
Q

How do nectins and nectin-like substances play a role in abnormal cancer cells?

A
  • may be deficient
  • lack of normal contact inhibition
  • overgrowth of cancer cells
17
Q

What are the phases of the cell cycle?

A
G0
G1
S
G2
M
G1 checkpoint
18
Q

What is the G0 phase?

A
  • resting phase

- cell has left the cycle and stopped dividing

19
Q

What is the G1 phase?

A

Cell growth in preparation for increased DNA synthesis

20
Q

What is the S phase?

A

DNA synthesis

21
Q

What is the G2 phase?

A

Cell growth preceding mitosis

22
Q

What is the M phase?

23
Q

What is the G1 checkpoint?

A
  • regulatory step preventing the move into DNA synthesis phase
  • prevents cell division
24
Q

What is another name for tumor suppressor genes?

A

anti-oncogenes

25
What do anti-oncogenes decrease when active?
Decrease risk of a cell becoming metastatic (cancerous)
26
What do anti-oncogenes code for?
proteins that: - have a repressive effect on the progression through the cell cycle - promote apoptosis - do both
27
Which gene is nicknamed "the guardian of the genome"?
P53 tumor suppressor gene
28
What does the P53 protein do?
changes gene expression to halt proliferation and trigger apoptosis when DNA is damaged
29
At what phase in the cell cycle does P53 halt cell division in response to DNA damage?
G1 phase
30
How often is the P53 gene found to be mutated or disrupted?
in more than 50% of all cancers
31
Why is P53 gene mutation so bad?
- suppresses normal apoptotic proteins | - cell continues to multiply