Researchers have identified six molecular and cellular traits that characterize most cancers. These six hallmarks of cancer are summarized in Table 13.1. In this chapter, we will focus on the first two hallmarks, namely growth signal autonomy and insensitivity to anti-‐growth signals.
Table 13.1 Ten Hallmarks of Cancer (Hanahan and Weinberg, 2000; Hanahan 2011)
1. Growth signal autonomy
Cancer cells can divide without the external signals normally required to stimulate division.
2. Insensitivity to growth inhibitory signals
Cancer cells are unaffected by external signals that inhibit division of normal cells.
3. 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.
4. 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.
5. 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.
6. Tissue invasion and metastasis
Normal cells generally do not migrate (except in embryo development). Cancer cells invade other tissues including vital organs.
7. Deregulated metabolic pathways
Cancer cells use an abnormal metabolism to satisfy a high demand for energy and nutrients.
8. Evasion of the immune system
Cancer cells are able to evade the immune system.
9. Chromosomal instability
Severe chromosomal abnormalities are found in most cancers.
Local chronic inflammation is associated with many types of cancer.
Dr. Todd Nickle and Isabelle Barrette-Ng (Mount Royal University) The content on this page is licensed under CC SA 3.0 licensing guidelines.