The entire medical field is based on opinion and wizardry. We're sicker and weaker than ever.
I've healed myself from various conditions by going carnivore.
Full disclosure: I have not read the article yet but gathered a sense of it from the comments here.
I like your citations. They make me think about a recent radio interview in Canada where an MD was discussing cervical Cancer. He would not say that vaccination for HPV prevented Cervical Cancer. He would only say that it prevented pre-cancerous lesions and Cervical cancer "is never seen without pre-cancerous lesions".
I can understand using scientific rigour to avoid jumping to conclusions. However it makes me wonder about Louis Pasteur and the discovery of micro-bacterial disease origins. Would he have said: "I can't say that these bacteria causes disease X but we have never seen disease X without the presence of these bacteria." ?
All that to say perhaps medical research has been going down the wrong path with Cancer. We have one clear case of viral "involvement". :-)
How big a stretch is it to extend research in that direction and look for more cases?
But not all cancers are caused by virus. Probably some of the multiple toxic compounds in the smoke of tobacco is the most known case. Radiation is also a well known cause. Even more info https://en.wikipedia.org/wiki/Carcinogenesis
From your wikipedia link, this technique sounds like a great way to find more cancer causing viruses.
"...developed a new method to identify cancer viruses based on computer subtraction of human sequences from a tumor transcriptome, called digital transcriptome subtraction (DTS)"
It's from 2008. There has been enormous improvements in DNA technology since that time.