There are some theories that everyone has cancer in them in microscopic amounts but most of the time the immune system keeps it in check. Cell division errors happen all the time but sometimes something happens that creates a cancer cell that the immune system doesn't recognize as foreign body and then manages to keep replicating until you have a tumor.
There are some theories that everyone has cancer in them in microscopic amounts but most of the time the immune system keeps it in check. Cell division errors happen all the time but sometimes something happens that creates a cancer cell that the immune system doesn't recognize as foreign body and then manages to keep replicating until you have a tumor.