genomic stability

Question 1

advantages of genomic instability

Answer 1

• activation of oncogenes
• gene fusions
• alteration of signalling pathways: amplification of signalling proteins or transcription factors
• increases genetic diversity
• accelerates evolution: enables cancer cells to develop new genetic adaptations
• promotes resistance to therapy
• immune evasion
• modulation of the TME: overexpression of factors, such as VEGF and stroma changing ligands like TGF - beta

Question 2

what does loss of telomeres produce

Answer 2

sticky ends that make chromosome fusions likely

Question 3

checkpoints G2M

Answer 3

• all checkpoints try to maintain homeostasis
• during mitosis multiple signals can stop or delay division most common being unconnected chromosomes and DNA damage

Question 4

mitotic checkpoint

Answer 4

• CDC20 activated APC complex when all chromosomes are attached
• degradation of cyclin B and securin allows mitosis to progress

Question 5

mitosis being a race

Answer 5

• division will happen first if cyclin B levels fall fast enough to reach the threshold to cause division
• cell death will happen first if damage signals accumulates faster than cyclin B levels fall
• targeting mitosis aims to stall cells long enough for the damage threshold to be reached first