8.2: Hallmarks of Cancer
Researchers have identified molecular and cellular traits that characterize most cancers. An original six hallmarks of cancer were identified and later four additional hallmarks were added (Hanahan and Weinberg, 2000; Hanahan and Weinberg, 2011 https://www.cell.com/fulltext/S0092-8674(11)00127-9 ).
Hallmarks of Cancer
- Growth signal autonomy: Cancer cells can divide without the external signals normally required to stimulate division.
- Insensitivity to growth inhibitory signals: Cancer cells are unaffected by external signals that inhibit division of normal cells.
- Evasion of apoptosis: When excessive DNA damage and other abnormalities are detected, apoptosis (a type of programmed cell death) is induced in normal cells, but not in cancer cells.
- Reproductive potential not limited by telomeres: Each division of a normal cell reduces the length of its telomeres. Normal cells arrest further division once telomeres reach a certain length. Cancer cells avoid this arrest and/or maintain the length of their telomeres.
- Sustained angiogenesis: Most cancers require the growth of new blood vessels into the tumor. Normal angiogenesis is regulated by both inhibitory and stimulatory signals not required in cancer cells.
- Tissue invasion and metastasis: Normal cells generally do not migrate (except in embryo development). Cancer cells invade other tissues including vital organs.
- Deregulated metabolic pathways: Cancer cells use an abnormal metabolism to satisfy a high demand for energy and nutrients.
- Evasion of the immune system: Cancer cells are able to evade the immune system.
- Chromosomal instability: Severe chromosomal abnormalities are found in most cancers.
- Inflammation: Local chronic inflammation is associated with many types of cancer.
Cancer hallmarks reflect genetic changes
Previous chapters have covered many topics that are related to these hallmarks.
For each hallmark, try to think of a gene or process that could be mutated to produce the effect.
Contributors and Attributions
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Dr. Todd Nickle and Isabelle Barrette-Ng (Mount Royal University) The content on this page is licensed under CC SA 3.0 licensing guidelines.