Learning Center Articles

Biology of Cancer

Biology of Cancer

  • Two major dysfunctions in the process of cancer development:
    • Defective cell proliferation (growth)
      • Stem cells
        • Undifferentiated cells
        • Ultimately differentiate and become mature, functioning cells of only that tissue
      • All cells are controlled by an intracellular mechanism that determines proliferation
        • Orderly process progressing from a state of immaturity to a state of maturity
        • Stable and will not change
      • Cancer cells grown in culture are characterized by loss of contact inhibition
        • Grow on top of one another and on top of or between normal cells
      • Cancer cells respond differently than normal cells to intracellular signals regulating equilibrium
        • Divide indiscriminately and continuously
          • Pyramid effect
    • Defective cell differentiation
      • Two types of genes that can be affected by mutation are
        • Protooncogenes
          • Regulate normal cellular processes such as promoting growth
          • Genetic locks that keep cells functioning normally
          • Mutations that alter their expression can activate them to function as oncogenes
        • Tumor suppressor genes
          • Suppress growth
          • Function to regulate cell growth
            • Prevent cells from going through the cell cycle
          • Mutations make them inactive
            • Result in loss of suppression of tumor growth