HMB265H1 Lecture Notes - Lecture 22: Melanoma, Contact Inhibition, Mitosis
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HMB265H1 Full Course Notes
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The first characteristic is the fact that theres uncontrolled cell proliferation. This stems from the fact that cancer cells have lost their ability to respond to outside signals. Cancer cells are unable to respond to regulation of extracellular signals. Most cells will only divide a certain amount of times and this is without any external signaling. The inducation of a tumor is caused by several independent mutations. Theres lots of genetic redundancy in genetically crucial processes. Further down the chain, theres more mutations that cause malignancy. Cancer increases with age because there more time to develop those mutations. Later stages of cancer are known to have more mutations in them than eallier stages. An early mutation could be a mutation in a tumor suppression gene. A later mutation would be the activation of oncogenes with the loss of more tumor suppressors. Whats known to be associated with lots of later cancers is the loss of the tumor suppressor p53.