2 What is It? Proto-oncogenes: genes that start cell division Oncogenes: “cancer genes”, caused by mutations in Proto-oncogenes, cause cells to divide constantlyTumor Suppressors: stop cell division, if mutated they won’t stop itThen Cancer is a group of cells that “forgot” how to stop dividing
3 Tumors Tumors: a large mass of rapidly dividing cells Types of Tumors: Benign: cannot spread to form new tumorsMalignant (cancerous): able to spread to other tissuesMetastasis: the spreading of tumorsTumors take away blood supply and nutrients from normal cells and interfere with normal cell functions
4 Causes of CancerAgeRadiation: UV light, x-rays, radioactive substancesCarcinogens: chemicals that mutate DNAGasoline, tobacco smoke, tobacco (chewed)Viruses: ex: Hepatitis = #1 cause of liver cancerHeredityAlcoholObesity
5 Protection from Cancer Avoid the aboveKeep immune system strong (exercise, sleep, avoid stress, eat right)Don’t drink, don’t smoke (secondhand included)Don’t sunburn!
6 Cancer Treatments Surgical removal of tumors Radiation: beams of radiation target/destroy tumorsChemotherapy: use of drugs to treat cancerTarget/destroy fast-dividing cells
7 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.