Cancer Flashcards
How does cancer occur?
Genetic alterations lead to unchecked cellular division and invasiveness. Accumulation of mutations in oncogenes and tumor suppressor genes
Where is cancer more likely to occur? Give examples
In tissues that are capable of self renewal.
Blood cells, which are constantly replenished by hematopoiesis.
Epithelial cells of mucosal tracts and skin have ongoing renewal because they’re at risk for damage by environmental exposures
Where is cancer less likely to occur?
Muscle and nervous system cells because they rarely regenerate
Define benign tumor
Tend to be encapsulated by connective tissue
Composed of normal cells
Not invasive to other tissues
Define malignant tumor
Not encapsulated
Composed of abnormal looking cells
Invasive
Define oncogenes
Genes that promote cellular division
Define tumor suppressor genes
Genes that inhibit cellular division
List cancer characteristics
- Stimulate own growth
- Ignore growth-inhibiting signals
- Avoid apoptosis
- develop angiogenesis
- Invade other tissue (metastasis)
- Replicate continuously
- Evade the immune system
What are carcinogens?
Agents that cause a predisposition to cancer
What are mutatgens?
Agents that cause genetic mutations. Many carcinogens are mutagens
List categories of carcinogens
- radiation (x-rays, UV, radioactive isotopes)
- chemical agents - inhalation, ingestion or skin contact can cause DNA damage
- growth promotors - hormones, cytokines
- some infectious microorganisms
What else can cancers develop from?
About 15% of cancers are associated with viral infections. Others are most often a combination of more than one carcinogen. Ex stomach cancer is associated with H. pylori infections
