I liked your explanation that cancer is caused by virus. So far I only found info on that on you tube from Professor G. Zajicek. As a non doctor this is what I was able to learn. I would like you to comment on my understanding, if possible. Cancer is an interaction between two processes a driving virus and host resistance. The tumor location is determined by something called viral tropism. For instance HBV infects only the liver. A weaken host tolerates a chronic inflation for a long time, instead of wiping it out, allowing virus to cause damage. The second line of defense is in the cell. Inside a cell it is either the virus which kills the cell and produces more virions or becomes an endosymbion and the cell is protected from similar viruses. Although virus does not cause directly a tumor (tumor is believed to be part of a repair process), only it's (virus) eradication can cure cancer.