Cancer Overview and Cell Behavior

Cancer Overview

• Cancer involves abnormal cell growth and reproduction.
• Normal cells have specialized functions and obey rules for growth, reproduction, and location.
• Cancerous cells ignore these rules, leading to rapid division and tumor formation.

Cell Behavior and Cancer

• Contact Inhibition: Normal cells stop dividing when they come into contact with other cells (preventing overcrowding).
• Contact Inhibition of Movement: Normal cells maintain their position within tissues.
• Contact Inhibition of Reproduction: Normal cells avoid dividing when there's no room.
• Cellular Senescence: As a cell divides, its descendants have reduced ability to divide.
• Cancer cells ignore these constraints, leading to uncontrolled growth.

Tumor Types

• Not all tumors are cancerous. Benign tumors are non-cancerous.
• Calluses, moles, and other similar growths are benign.
• Cancerous tumors are called malignant.
• Malignant tumors are classified according to the tissue type they affect:
  • Carcinomas: Skin and nerve tissues
  • Sarcomas: Bone and muscle tissues
  • Lymphomas: Solid tumors in blood-forming and lymphatic tissues
  • Leukemia: Cancers within white blood cells

Metastasis

• Metastasis: The spread of cancer cells throughout the body.
• Cancer cells often travel through lymphatic fluids.
• Lymph nodes are frequently checked for cancer cells.

Cancer Causes

• Carcinogens: Substances that damage DNA and cause mutations, leading to cancer. Examples include asbestos, UV light, benzene, tobacco, DDT, and radiation.
• Viral Agents: Certain viruses can cause mutations in infected cells.
  • Human Papillomavirus (HPV): Associated with increased risk of uterine and other reproductive cancers.
  • Hepatitis Viruses (especially Hepatitis C): Associated with increased risk of liver cancer.
• Cancer Genes:
  • Oncogenes: Genes that, when mutated, can cause uncontrolled cell growth
  • Proto-oncogenes: Normal genes that promote cell growth and division. These genes can be mutated and become oncogenes

Cancer Treatment

• Cancer treatments aim to destroy cancerous cells.
• Surgical removal: Directly removing cancerous tissue.
• Radiation therapy: Using high-energy radiation to kill cancer cells.
• Chemotherapy: Using powerful drugs to kill cancer cells. More toxic to cancer cells, than normal cells, due to different metabolic rates.. It is generally used to treat advanced or aggressive cancers.

This quiz covers the fundamentals of cancer, focusing on abnormal cell growth and reproduction. It explains the differences between benign and malignant tumors, as well as important concepts like contact inhibition and cellular senescence. Test your knowledge on these crucial aspects of cancer biology.