Cancer progresses through accumulation of multiple mutations Each
- Slides: 13
Cancer progresses through accumulation of multiple mutations Each successive mutation allows those cells to proliferate more quickly than those around it.
Cancer is a genetic disease, but not usually inherited. • Most cells in the body are somatic cells. • Most mutations are in the somatic cells. • Germline mutations are inherited by offspring
…but it sometimes is inherited and runs in families. • Each cell has 2 copies of each tumor suppressor gene. • Both copies must be mutated for cancer to form. • If first mutation is inherited, all cells are susceptible to 2 nd mutation.
2 -hits in retinoblastoma • Cancer of the retina • Small tissue with only one tumor suppressor gene active. • Most people get only 1 mutation in any given cell – No cancer • Some people get 2 mutations in any given cell – Cancer in one eye • Some people inherit mutation in all of their cells. Next mutation causes cancer. – Cancer in both eyes usually by age 5.
What causes mutations to occur and spread? • Mutations may be inherited • Carcinogens – any agent involved in the promotion of cancer – Smoke (esp. cigarette smoke) – Radiation / sun – Chemicals / solvents – Infectious diseases (eg Human papillomavirus) – Food (esp. charred meat) – Hormones (eg. Estrogen) – Many, many others!
External signals that control cell proliferation: growth factors
External signals that control cell proliferation
Cell proliferation: tumors recruit blood vessels to supply oxygen and nutrients. Tumors secrete Growth factors that promote angiogenesis (formation of blood vessels
Tumor growth First mutation causes rapid growth 2 nd mutation increases growth rate and changes appearance of cells After recruiting blood supply, may metastasize to other tissues
• Family history Risk Factors – But only 5% of cancers are inherited • Tobacco use – 30% of all cancers and 87% of lung cancer • Smokeless tobacco – Oral and pancreatic cancers • Diet – Eat fruits and vegetables – Avoid charred meats – Avoid preserved meats
Risk factors • Being sedentary – Moving helps push food through your intestines, limiting exposure to carcinogens • Alcohol • Irregular medical care – Cancer goes undetected • Sunlight (UV and other radiation) • Chemical carcinogen exposure • Infectious agents (eg. HPV for cervical cancer)
Treatment options • Surgery • Removal of cancerous tissue • Radiation • Kills cancer cells (usually targeted to specific tissue) • Chemotherapy • Uses chemicals to kill cancer cells (throughout body) • Biological immunotherapy • Strengthens immune system • Transplants • Particularly Bone Marrow for leukemias
- Cancer mutations
- Cancer mutations
- Cancer mutations
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