Cancer and therapies

Question 1

What does quiescent mean?

Answer 1

• not actively dividing to create new cells, but still retain the ability to proliferate

Question 2

Are all tumours considered cancer?

Answer 2

• no
• benign tumours are not cancer as they do not spread to nearby tissues or metastasize
• they usually do not recur after removal

Question 3

What are cancerous tumours called?

Answer 3

• malignant
• spread to nearby tissues and metastasize (travel to distant sites to form new tumours)

Question 4

How are cancer cells different than normal cells?

Answer 4

• divide in absence of growth signals
• ignore signals telling it to stop dividing or signals for apoptosis
• invade nearby areas
• angiogenesis (blood vessels grow towards the tumour)
• avoid detection/destruction
• accumulate many changes in DNA
• often use different metabolic processes than normal cells

Question 5

What mutations occur which may lead to cancer?

Answer 5

• inherited DNA gene mutation
• DNA mutation during DNA replication
• DNA mutation due to exposure to mutagenic substances/agents

Question 6

What is a somatic mutation?

Answer 6

• any gene mutation that happens after conception

Question 7

What is a nonsense, missense, and frameshift mutation?

Answer 7

• missense - single base is changed (one amino acid)
• nonsense - mutation changes the base which now codes for a stop codon
• frameshift - deletions or insertions which change the entire protein as now the sequence is completely changed

Question 8

How can chromosome rearrangements lead to cancer?

Answer 8

• piece of chromosome is lost, moves to different location, flips direction, or is repeated
• these changes can alter important genes