Here is what we learned recently about somatic evolution and cancer:
1. Mutations arise in virtually every tissue of our body, as a part of normal development and ageing doi.org/10.1101/416339. As a rule of thumb about 1 mutation is introduced at every cell division.
1. Mutations arise in virtually every tissue of our body, as a part of normal development and ageing doi.org/10.1101/416339. As a rule of thumb about 1 mutation is introduced at every cell division.
2. Somatic mutations shed light on the first cell divisions in life, informing us about early embryogenesis and how the cells in different parts of our bodies are related to each other via their shared mutations. dx.doi.org/10.1038/nature… dx.doi.org/10.1038/nature…
3. In some cases this allows one to draw detailed conclusions about the homeostatic dynamics of an adult organ, exemplified beautifully in recent work on normal blood by Henry Lee-Six, @scienceadvocacy and colleagues. doi.org/10.1038/s41586… 
4. The accumulation of mutations is part of normal ageing and most cells accumulate a mutation load not too dissimilar from cancer cells. This is exemplified by a recent study on 571 normal colonic crypts, by Henry Lee-Six and others. doi.org/10.1101/416800
5. In some tissues, mutations lead to microscopic clonal expansions, fuelled by mutations in genes commonly (but not always) found mutated in cancer, as evidenced in normal skin dx.doi.org/10.1126/scienc… and in the oesophagus by @imartincorena, and also in clonal haematopoiesis.
6. The principle that some mutations accumulate rather constantly over a lifetime can be used to time when certain genetic aberrations in adult cancers have occurred. This can be during childhood in as in the example of Kidney cancer by @Tom_J_Mitchell dx.doi.org/10.1016/j.cell…
7. As part of a large consortium effort, we have recently conducted a pan-cancer analysis of 2,658 cancer genomes corroborating these timescales, indicating that by conservative estimates, many mutations precede cancer diagnosis by a decade or more. doi.org/10.1101/161562
8. The overall conclusion being that somatic evolution is a lifelong process. It emerges that the boundary between between normal evolution and cancer is more fluent than previously thought. //
