HMB265H1 Lecture Notes - Lecture 21: Contact Inhibition, Autocrine Signalling, Irradiation
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HMB265H1 Full Course Notes
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Document Summary
More than 100 diseases in which cells grow out of control and can destroy healthy tissue. Caused by failures in the mechanisms that control growth, proliferation and apoptosis. Results from genetic damage (mutation) or altered gene expression. They allow for increased growth and proliferation: contact inhibition: normal cells slow their proliferation rate as they begin to contact other cells. This is inhibited in cancer cells: cell death: cells do not undergo programmed cell death (apoptosis) and are not killed by irradiation. Irradiation normally causes cells to undergo apoptosis to prevent a mutated cell from continuing to replicate: gap junctions: cancer cells do not have gap junctions. Defects in replication and repair machinery results in unfaithful replication of dna. Mismatches are not repaired and are passed on to clonal descendants. This occurs in somatic cells and thus are not passed on to progeny.
