What is cancer? Is it contagious?
What is It? Proto-oncogenes: genes that start cell division Oncogenes: “cancer genes”, caused by mutations in Proto-oncogenes, cause cells to divide constantly Tumor Suppressors: stop cell division, if mutated they won’t stop it Then Cancer is a group of cells that “forgot” how to stop dividing
Tumors Tumors: a large mass of rapidly dividing cells Types of Tumors: Benign: cannot spread to form new tumors Malignant (cancerous): able to spread to other tissues Metastasis: the spreading of tumors Tumors take away blood supply and nutrients from normal cells and interfere with normal cell functions
Causes of Cancer Age Radiation: UV light, x-rays, radioactive substances Carcinogens: chemicals that mutate DNA Gasoline, tobacco smoke, tobacco (chewed) Viruses: ex: Hepatitis = #1 cause of liver cancer Heredity Alcohol Obesity
Protection from Cancer Avoid the above Keep immune system strong (exercise, sleep, avoid stress, eat right) Don’t drink, don’t smoke (secondhand included) Don’t sunburn!
Cancer Treatments Surgical removal of tumors Radiation: beams of radiation target/destroy tumors Chemotherapy: use of drugs to treat cancer Target/destroy fast-dividing cells
Question (answer in your notes) Hair grows from hair follicles, pockets of continually dividing cells in the outer layer of the skin. New cells are added to the base of a hair shaft, inside each follicle. Use what you have learned to explain why cancer patients often lose their hair when receiving chemotherapy and grow more hair after chemotherapy stops.