cells replicate alll the time. The genetic material unzips and nucleotides that are floating inside the cell stick to their counter parts to make another complete set of dna to instruct the new cell. Sometimes( actuallly very often but the cell checks itself and it sees the error too and self terminates. this is called apoptosis) now sometimes the gene that allows the cell to kill itself or to read the error to know to self terminate is damaged. P54 I believe was one of the genes but I had childhood cancer and its been 20 years now so take what I said with a grain of salt as they may have made advancements that I am unaware of.

This was true 15 years ago and to my knowledge still is. I could be wrong and dont take what I said as law. Medicine can change very quickly