Cancer

• What is cancer a result of?

  Mutations in genes regulating mitosis
• How does a gene mutation affect mitosis?

  It can create a non-functioning protein
• What happens when mitosis is uncontrolled?

  A tumor is formed
• What are the two types of tumors?

  Benign and malignant tumors
• What characterizes benign tumors?

  They grow slowly and are non-cancerous
• Why are benign tumors easier to remove?

  They are contained within a membrane
• What is a potential danger of a benign tumor in the brain?

  It can put pressure on brain tissue
• How do malignant tumors differ from benign tumors?

  They grow quickly and are cancerous
• What does metastasize mean in relation to malignant tumors?

  They can spread to new locations in the body
• Why do malignant tumors grow rapidly?

  They develop their own blood supply
• Why is surgery often complemented with radiotherapy or chemotherapy for malignant tumors?

  To ensure all cancer cells are removed
• What are oncogenes?

  Mutated versions of proto-oncogenes
• What role do proto-oncogenes play in cell division?

  They initiate DNA replication during interphase
• What happens when a proto-oncogene mutates into an oncogene?

  It causes constant cell division
• What do tumor suppressor genes do?

  They slow down cell division
• What occurs if a tumor suppressor gene is mutated?

  Cell division continues at a rapid rate
• Which two tumor suppressor genes are linked to breast cancer?

  BRCA1 and BRCA2
• What is abnormal methylation in relation to tumor suppressor genes?

  It can turn off the gene without mutation
• How does increased estrogen concentration relate to breast cancer risk?

  It can interfere with gene transcription
• Why do tumors in breast tissue grow rapidly after menopause?

  Estrogen is produced in fat cells
• How does estrogen affect proto-oncogenes?

  It can activate them, promoting cell division
• What is the relationship between tumors and estrogen production?

  Tumors can increase estrogen production
• What are the key properties of benign tumors?

  • Grow slowly
  • Non-cancerous
  • Produce adhesion molecules
  • Surrounded by a membrane
  • Localized impacts
  • Easier to remove surgically
• What are the key properties of malignant tumors?

  • Grow quickly
  • Cancerous
  • Do not produce adhesion molecules
  • Not contained within a membrane
  • Can metastasize
  • Develop their own blood supply
• What are the four key ideas for tumor development?

  1. Gene mutations in cell division genes
  2. Abnormal methylation of genes
  3. Increased estrogen concentrations
  4. Mutations in tumor suppressor genes or oncogenes
• How does methylation affect tumor suppressor genes and oncogenes?

  • Hyper-methylation: turns off tumor suppressor genes
  • Hypo-methylation: permanently activates oncogenes
• How does estrogen influence breast cancer risk in post-menopausal women?

  • Produced in fat cells after menopause
  • Interferes with transcription of cell cycle genes
  • Can lead to tumor growth and increased estrogen production