2.2.1 Cancer

• What happens to human cells after differentiation?

  They lose ability to divide by mitosis
• What results from uncontrolled division of cells?

  Formation of cancer cells and tumours
• What type of tumours remain localized?

  Benign tumours
• What happens if a benign tumour continues to grow?

  It compromises surrounding tissues
• How are benign tumours typically treated?

  By surgery or radiation
• What is metastasis?

  Cells traveling to form new tumours
• What percentage of cancers arise from DNA replication mutations?

  About 50%
• Why is there no single treatment for cancer?

  Due to various biochemical reasons
• What are the main treatments for cancer?

  • Disrupting the cell cycle
  • Preventing DNA replication
  • Disrupting spindle fibres/formation
  • Chemotherapy
  • Monoclonal antibody treatments
• How does chemotherapy work against cancer cells?

  It targets rapidly dividing cancer cells
• What is a drawback of chemotherapy drugs?

  They affect non-cancerous rapidly dividing cells
• What does the graph in Figure 3 illustrate?

  Changes in healthy and cancer cells during treatment
• Why might a chemotherapy drug not be given more frequently?

  To avoid harming healthy cells excessively
• Why might the dose of a chemotherapy drug not be increased?

  To prevent severe side effects in patients
• What is the role of phagocytes in the immune response?

  To engulf and destroy pathogens
• How do antibodies recognize antigens?

  By binding to specific antigen sites
• Why are antigens significant in cancer treatment?

  They help target specific cancer cells
• What is a consequence of chemotherapy on healthy cells?

  It can damage rapidly dividing healthy cells
• How does Herceptin work in breast cancer treatment?

  It targets specific cancer cell receptors