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SSC- Biology of Cancer > Carciogenesis > Flashcards

Flashcards in Carciogenesis Deck (93)
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1

What is cancer? 

A group of diseases all sharing similar characteristics

2

What are the characteristics that all cancers share? 

They are all abnormal, uncontrolled growths of cells. They all show inappropriate proliferation, invasion, and metastasis 

 

3

What are the characteristics of a benign tumour? 

  • Slow growth
  • Non-invasive
  • No metastasis

 

4

What are the characteristics of a malignant tumour?

  • Rapid growth
  • Invasive
  • Potential for metastasis

 

5

What is the increase in incidence of cancer due to? 

  • Lifestyle changes
  • Increased screening

 

6

What is carciogenesis? 

The process of transformation of a 'normal' cell to a cancer cell

7

What are the stages in carciogenesis? 

  1. Initiation
  2. Promotion
  3. Progression
  4. Transformation
  5. Evolution
  6. Metastasis

 

8

What happens in initiation? 

A mutation in stem cells is acquried when they are exposed to a carcinogen, and you get unrepaired DNA damage

9

What happens in promotion? 

There is induction of cell division, where the cancer starts from a single cell that has a selective advantage over other cells within the same tissue 

10

How does promotion lead to progression? 

Increased proliferation means increased mutations and therefore an increased advantage

11

What happens in progression? 

  • Conversion
  • Propagation
  • Dedifferentiation 

 

12

What is there a potential for in transformation? 

Regression

13

What can be produced in cancer evolution?

A drug resistant clinical tumour 

14

What happens in cancer metastasis? 

Spread of transformed cells 

15

What stages of carciogenesis can be used to treat cancer? 

Can enter at any stage to try and prevent disease

16

What does mutation lead to in colorectal carciogenesis? 

Inactivation of the APC gene 

17

What will an inactivation of the APC gene in colorectal carcinogenesis cause? 

May cause a change in frequency in division, which leads to an increase in stem cells. This will develop over time into a cluster of APC-less cells with stem cell properties 

18

What might the 'second hit' be in colorectal carcinogenesis? 

Inactivation of Ras

19

What is the result of the inactivation of Ras in colorectal carcinogenesis? 

Increased selective advantage 

20

What might the third hit be in colorectal carcinogenesis? 

Inactivation of p53

21

What happens after the third hit in colorectal carcinogenesis? 

Increased growth, starts to form an adenoma 

22

What does the forth hit in colorectal carcinogenesis lead to? 

The rapid development of cancer

23

What extracellular/environmental factors can cause genes to mutate? 

  • Binding of ultimate carcinogens
  • Ionising radiation/UV
  • DNA translocation

 

24

What do ultimate carcinogens do? 

Bind to DNA and alter the sequence

25

What effect does ionising radiation and UV have on DNA? 

Causes strand breaks and cross links

26

When may DNA translocation cause mutations? 

When it is translocation to transcriptionally active regions

27

What intracellular factors can cause mutations? 

  • Misinterpretation of code
  • Polymerase slippage/base misalignment
  • Ineffective repair

 

28

What can all mutations potentially affect? 

Cellular signalling

29

What can act as initiating stimuli in carcinogenesis?

  • Chemical carcinogens
  • Oncogenic viruses
  • Radiation
  • UV light
  • Oxygen free radicals
  • Replication errors

 

30

When can oxygen free radicals act as an initiating stimuli for carcinogenesis? 

When there is an imbalance between their production (which happens naturally) and their removal