Cell Division and Cancer

Cell Division Going Wrong: Cancer

• Cancer is uncontrolled cell division
• A cancer cell continues dividing despite signals from the nucleus or surrounding cells to stop growing and dividing
• Uncontrolled growth forms a lump or tumor

Cell Growth Rates and Cancer

• Cancer cells are large, variably shaped, and have many dividing cells with disorganized arrangement
• Normal cells have a variation in size and shape, with loss of normal features.

Normal Cells vs. Cancerous Cells

• Normal Cells: Many cells that continue to grow and divide with variations in size and shape of cells
• Cancerous Cells: Nucleus that is larger and darker than normal, abnormal number of chromosomes arranged in a disorganized fashion, cluster of cells without a boundary.

Normal Cell vs. Cancer Cell

• Normal Cells:
  • Make exact copies through mitosis
  • Reproduce for about 50-60 cell divisions
  • Stick together to form masses
  • Self-destruct when damaged
• Cancer Cells:
  • Make exact copies through mitosis
  • Do not stop reproducing
  • Do not stick to other cells; behave independently
  • May move to another location in the body

Normal vs. Cancer Cell (Diagram)

• Diagram contrasting normal cell division (apoptosis) with uncontrolled cancer cell division (b).

Cell Growth Rates and Cancer - Benign Tumors

• Benign tumor: cells of a tumor that stay together and have no serious effect on surrounding tissues, except for crowding them
• Not cancerous, grow only locally and cannot spread by invasion or metastasis

Cell Growth Rates and Cancer - Malignant Tumors

• Malignant tumor: a mass of cells that interferes with functions of neighboring cells and tissues
• Can interfere with hormones or enzymes or destroy surrounding tissues
• Cancerous; cells invade neighboring tissues, invade blood vessels, and metastasize

Benign vs. Malignant Tumors (Summary)

• Benign: tumor cells grow only locally and cannot spread by invasion or metastasis
• Malignant: cells invade, enter blood vessels, and metastasize to different sites

Metastasis

• Metastasis: when cancer cells break away from the original tumor and move to another part of the body
• If the cells settle, they can start another tumor
• This process is dangerous because it accounts for one of the reasons cancer is a dangerous disease.

Metastasis (Diagram)

• Diagram illustrating the process of metastasis, showing cells breaking away and forming new tumors

Causes of Cancer

• DNA Replication: Every cell division duplicates its DNA. Normally the genetic information is identical to the parent cell, however, sometimes random changes called mutations occur.
  • These mutations can lead to the cancer cell behaving abnormally, causing repeated uncontrolled cell division until nutrients are depleted and cell growth stops.

Causes of Cancer - Contributing Factors

• Mutations are caused by carcinogens, such as tobacco smoke, radiation, viruses, chemicals, and some organic solvents.

Causes of Cancer - Heredity

• Some cancers may be partially hereditary. Some DNA passed down from one generation to another may lead to disease. Examples include breast and colon cancers.
• A genetic link makes developing certain cancers more likely but it does not guarantee developing cancer

Smoking and Cancer

• Lung cancer is a prevalent cancer type in people over 40
• Smoking is responsible for 90% of lung cancer cases.
• Carcinogens in smoke affect organs other than just the lungs.
• Most smoking related cancers can be avoided by quitting or abstaining from smoking and exposure to secondhand smoke

Cancer Screening

• Cancer screening involves checking for cancer, even without symptoms
• Often done at home or doctors' offices
• Important for people with family history of certain cancers (breast and colon)
• Genetic screening can identify inherited DNA linked to cancer.
• Screening increases the chance for early cancer detection and successful treatment

Taking Responsibility for Health

• Women: Breast self-exams to check for lumps, Pap tests for cervical cancer
• Men: Testicular self-exams for testicular cancer, PSA tests for prostate cancer (age 50+)
• All: Blood tests for colon cancer, regular skin checks by a doctor or dermatologist; using ABCD of moles for self-examination (Asymmetry, Border, Color, Diameter) for potential skin cancers/moles

Reducing Your Risk of Cancer

• Prevention and early detection
• Healthy diet: fruits, vegetables, limited fatty meats, certain "superfoods" (tomatoes, etc.)
• Healthy weight & exercise: maintaining a healthy weight and regular exercise can reduce risk of some cancers.

Diagnosing Cancer

• Symptoms: Swelling, discomfort, fatigue, or unexplained weight loss
• Early diagnosis increases chances of successful treatment.

Imaging Technologies

• Endoscopy: Used to examine colon cancer
• X-rays: Examine bones and lungs, though can damage DNA in rapidly dividing cells. Other body parts like bones and lungs, damage can sometimes occur, particularly to rapidly dividing cells (including a growing fetus).
• Ultrasound: Creates digital image of soft tissues like the heart and liver.
• CT Scan: Uses multiple X-rays from different angles to view specific body areas.

Imaging Technologies - continued

• MRI: uses radio waves and a strong magnetic field to create detailed images of internal body structures.

Examining Cells

• Blood cells: Blood samples can help detect abnormalities like leukemia
• Tumor cells: Biopsy allows viewing the structure and testing for genetic abnormalities.

Cancer Cell Characteristics

• Cancer cells are often irregularly shaped and can sometimes be smaller or larger than surrounding cells
• Diagnosis often involves determining tumor origins, growth rates and spread, to better understand if and how the treatment will be effective and to predict patient outcome

Treatment for Cancer

• Surgery: Physically removing the cancerous tissue; works well when the tumor is easily accessible
• Chemotherapy: Uses drugs to slow or stop cancer cell growth and division, often targeting rapidly dividing cancerous cells
• Radiation: Damages DNA in cancerous cells, minimising side effects by concentrating the radiation beam on the tumor
• Biophotonics: Uses light beams for detection and treatment of cancerous cells. Offers fewer side effects than traditional radiation because the light beam can more effectively target the cancerous cell.
• Genomics: Identify gene mutations, aiming to create personalized and effective cancer treatments which focuses on the genetic drivers behind the cancer.

Explore the mechanisms of cell division and how it can lead to cancer. This quiz examines the differences between normal and cancerous cells, including their structure and growth patterns. Test your knowledge on how uncontrolled cell division occurs and its implications.