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These types of mutations are usually prompted by environmental causes, such as ultraviolet radiation or any exposure to certain harmful chemicals, and can cause diseases including cancer. [ 91 ] With plants, some somatic mutations can be propagated without the need for seed production, for example, by grafting and stem cuttings.
However, once a cancer is formed it continues to evolve and to produce sub-clones. It was reported in 2012 that a single renal cancer specimen, sampled in nine different areas, had 40 "ubiquitous" mutations, found in all nine areas, 59 mutations shared by some, but not all nine areas, and 29 "private" mutations only present in one area. [35]
Other carcinogens may cause cancer through a variety of mechanisms without producing mutations, such as tumour promotion, immunosuppression that reduces the ability to fight cancer cells or pathogens that can cause cancer, disruption of the endocrine system (e.g. in breast cancer), tissue-specific toxicity, and inflammation (e.g. in colorectal ...
A cancer syndrome or family cancer syndrome is a genetic disorder in which inherited genetic mutations in one or more genes predisposes the affected individuals to the development of cancers and may also cause the early onset of these cancers. Although cancer syndromes exhibit an increased risk of cancer, the risk varies.
DNA may be modified, either naturally or artificially, by a number of physical, chemical and biological agents, resulting in mutations. Hermann Muller found that "high temperatures" have the ability to mutate genes in the early 1920s, [2] and in 1927, demonstrated a causal link to mutation upon experimenting with an x-ray machine, noting phylogenetic changes when irradiating fruit flies with ...
If, through mutation, normal genes promoting cellular growth are up-regulated (gain-of-function mutation), they predispose the cell to cancer and are termed oncogenes. Usually, multiple oncogenes, along with mutated apoptotic or tumor suppressor genes, act in concert to cause cancer. Since the 1970s, dozens of oncogenes have been identified in ...
Radiation is a more potent source of cancer when combined with other cancer-causing agents, such as radon plus tobacco smoke. Radiation can cause cancer in most parts of the body, in all animals and at any age. Children are twice as likely to develop radiation-induced leukemia as adults; radiation exposure before birth has ten times the effect ...
Incidental, or natural mutations occur through errors during replication and repair, either spontaneously or due to environmental stressors. Intentional modifications are done in a laboratory for various purposes, developing hardier seeds and plants, and increasingly to treat human disease. The use of gene editing technology remains controversial.