Insights into Cancer and Its Development

Sep 17, 2024

Notes on Cancer Presentation

Introduction to Cancer

  • Video shown to inspire interest in cancer research.
  • Progress and challenges in cancer research are highlighted.

Current Cancer Statistics

  • Approximately 1.4 million new cancer cases in the U.S. (excluding skin cancers).
  • Estimated 560,000 deaths due to cancer in the U.S. and 8 million worldwide.
  • More deaths from cancer annually than from malaria, TB, and HIV/AIDS combined.
  • Lifetime risk: 1 in 2 for men, 1 in 3 for women.
  • 1 in 4 deaths in the U.S. attributed to cancer.
  • Cancer is now the leading cause of death, surpassing cardiovascular disease.

Understanding Cancer

  • Lung Cancer: Common and diagnosed via chest x-rays or CT scans.
    • Can be identified by dark masses, indicating tumors.
  • Leukemia: Involves an abnormal increase in white blood cells.
    • Blood smears show excessive nucleated white blood cells.
  • Colon Cancer: Detected by colonoscopy.
    • Early signs include polyps (benign tumors) which can be removed.
    • More advanced cancers spread and are harder to treat.

Stages of Cancer Development

  1. Normal Cells: Growth on a basement membrane.
  2. Hyperplasia: Increased cell number without abnormal structure.
  3. Adenoma: Benign tumors that can be removed.
  4. Malignant Tumors: Aggressive and destructive, capable of spreading (metastasis).
    • Metastatic tumors can arise from primary tumors and are the most lethal.

Cancer Terminology

  • Hyperplasia: Increased cell number, normal architecture.
  • Benign Tumors: Not cancerous, non-aggressive.
  • Malignant Tumors (Cancer): Aggressive, invasive, capable of metastasis.
  • Carcinomas: Cancers of epithelial tissues (e.g., lung, breast).
  • Sarcomas: Cancers of connective tissues.
  • Leukemias: Excess cells in the blood; Lymphomas: Tumors of lymph organs.

Causes of Cancer and Genetic Basis

  • Cancer is a genetic disease caused by alterations in DNA.
    • Can be due to inherited mutations and mutations acquired over time.
  • Aneuploidy: Abnormal chromosome numbers in cancer cells.
  • Carcinogens: Substances that cause cancer, often act as mutagens.
    • Example: Bruce Ames' test for mutagenicity.

Environmental and Genetic Mutagens

  • Exogenous Mutagens:
    • Tobacco smoke (benzo[a]pyrene and other carcinogens).
    • Sunlight and UV rays causing skin cancer.
    • Dietary factors, e.g., barbecued meats.
  • Endogenous Mutagens:
    • Errors during DNA replication and defects in DNA repair mechanisms.
    • Reactive oxygen species produced during metabolism.

Clonal Evolution Theory

  • Cancer develops through a series of mutations over time (5-10 mutations needed).
  • Clonal Evolution: Progression from normal cells to malignant tumors through a gradual accumulation of mutations.

Conclusion

  • The lecture emphasizes the complexity of cancer and the importance of understanding its genetic basis and development mechanisms.
  • Future discussions will focus on specific genes mutated in cancers.