Cancer

• Cancer


  Result of mutations in genes that regulate mitosis
• Mutations in genes regulating mitosis


  • Create non-functioning protein
  • Leads to uncontrolled mitosis and cell division
  • Creates a tumor
• Benign tumor


  Non-cancerous, grows slowly, produces adhesion molecule to stick to one location, surrounded by membrane/capsule
• Malignant tumor


  Cancerous, grows rapidly, does not produce adhesion molecule, not contained in membrane, can metastasize and spread to new locations
• Benign tumor location


  Even if benign, can be dangerous if located in brain due to pressure on brain tissue
• Malignant tumors


  • Grow rapidly
  • Cells become unspecialized
  • Do not produce adhesion molecule
  • Not contained in membrane
  • Can metastasize and spread
  • Can develop own blood supply
• Removing malignant tumors


  1. Surgery often complemented with radiotherapy or chemotherapy

  2. Difficult to ensure all tumor cells are removed to prevent recurrence
• Oncogenes


  Mutated version of proto-oncogenes, permanently activate cell division
• Tumor suppressor genes


  Produce proteins that slow down cell division and cause cell death of mutated cells
• Mutations in BRCA1 and BRCA2 tumor suppressor genes linked to breast cancer
• Epigenetics - Abnormal methylation


  • Hypermethylation of tumor suppressor genes turns them off
  • Hypomethylation of oncogenes/proto-oncogenes keeps them permanently turned on
• Increased estrogen concentrations


  • Can interfere with transcription of cell cycle genes, leading to tumor formation
  • Tumor can then encourage more estrogen production, increasing tumor growth
• Women at higher risk of breast cancer after menopause due to increased estrogen production in breast fat cells