Role of mutations in dev. Of cancer

• How do cancer cells arise?

  • mutations in proto-oncogenes and tumour suppressor genes
  • activation of telomerase gene -> removes natural limit on number of times a cell can divide
• Mutations in proto-oncogenes and tumour suppressor genes can cause cell to bypass cell cycle checkpoints -> dysregulation of cell cycle checkpoints -> cells dividing uncontrollably -> increased accumulation of mutations in this cell leads to formation of cancer cell
• When is a cell most susceptible to mutations?

  When it is replicating its DNA during S phase of cell cycle
• Hate rate of mitosis increases the number of times cells replicate -> increasing likelihood of mutation