This is not true. Some cancers are caused by viruses. Many oncogenes were initially discovered in viruses. But the majority of tumors are definitely not caused by viruses.
This was a hypothesis in the field for a number of years, and has been disproven. If you want a good overview of the history of cancer, I recommend “The Emperor of All Maladies” by Siddhartha Mukherjee.
This was a hypothesis in the field for a number of years, and has been disproven. If you want a good overview of the history of cancer, I recommend “The Emperor of All Maladies” by Siddhartha Mukherjee.