Two-hit hypothesis
The Knudson hypothesis, also known as the two-hit hypothesis, is the
Knudson performed a statistical analysis on cases of
Knudson suggested that two "hits" to DNA were necessary to cause the cancer. In the children with inherited retinoblastoma, the first mutation in what later came to be identified as the
It was later found that
Related ideas
Field cancerization may be an extended form of the Knudson hypothesis. This is the phenomenon of various primary tumors developing in one particular area of the body, suggesting that an earlier "hit" predisposed the whole area for cancer.[citation needed]
Announced in 2011, chromothripsis similarly involves multiple mutations, but asserts that they may all appear at once. This idea, affecting only 2–3% of cases of cancer, although up to 25% of bone cancers, involves the catastrophic shattering of a chromosome into tens or hundreds of pieces and then being patched back together incorrectly. This shattering, it is presumed, takes place when the chromosomes are compacted during normal cell division, but the trigger for the shattering is unknown. Under this model, cancer arises as the result of a single, isolated event, rather than the slow accumulation of multiple mutations.[4]
The exact function of some tumor suppressor genes is not currently known (e.g.
References
- OCLC 1089396489.)
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: CS1 maint: location missing publisher (link) CS1 maint: others (link - PMID 5279523.
- PMID 15282542.
- PMID 21215367.
- ISBN 9780323296359.