cancer

• acquired mutations: occur in individual cells after fertilisation
• tumour suppressor genes:

  • when functioning normally, produce proteins that stop cells dividing or cause them to self-destruct (apoptosis)
  • if mutated, protein is not produced so cells divide uncontrollably
• proto-oncogenes:

  • normally, stimulate cell division by producing proteins that make cells divide
  • when mutated, gene is overactive, stimulating cells to divide uncontrollably
• appearance of tumour cells:

  • irregular shape
  • larger and darker nucleus
  • more than one nucleus
  • don't produce all proteins required for proper function
  • different antigens on their surface
  • don't respond to growth regulating processes
  • divide more frequently than normal cells
• methylation:

  • add CH3 to gene
  • controls whether gene is transcribed
  • hyper or hypo methylation causes issues
• how abnormal methylation affects tumour suppressor genes:

  • hypermethylated
  • not transcribed
  • proteins that slow cell division not produced
  • cells divide uncontrollably
• how abnormal methylation affects proto-oncogenes:

  • hypomethylated
  • act as oncogenes
  • increase production of protein stimulating cell division
  • cells divide uncontrollably
• oestrogen:

  • naturally stimulates breast cells to divide, so more divisions increases chances of mutation
  • if cells do become cancerous, oestrogen could further stimulate division, forming tumours quickly
  • oestrogen could introduce mutations directly into DNA of certain breast cells, further increasing risk of cancer