Well, canker sores which are actually herpes simplex (HSV1) are caused by a virus that you get for life, and when not active lives on the ganglion of your nerves. HSV1 and 2 has been associated with other viruses that do cause cancers. While this is not definitive proof of an involvement in the development of a malignancy, or even a symbiotic relationship between the viruses, it may speak to a much simpler idea, which would be a genetic predisposition to be susceptible to viral infections of all types. If that was a familial / passed on trait, it could be a genetic vehicle or opportunity for initiation. Just a thought with no evidence to back it up. We are off in an area here where there are no real answers only educated best guesses.

David, since these patients have been tested for HPV and found negative, another strain would show up in the HPV scan - so your idea that it is a different HPV isn't a correct possibility. Sub typing to figure out which HPV is another step after determining HPV itself. And this is done as a matter of routine when a OSCC comes up HPV+ to confirm it is 16. There have been occasional other types found with 16 when sub typing OSCC, but they are so infrequent, and often non oncogenic, that researchers consider them non consequential artifacts.

I want to remind people that in families common risk factors are often shared. Smokers live with smokers, people who eat poor, fatty diets share their bad habits, and pass the habit off to their children through socio-behavioral means. So you have to be careful to distinguish between what is a genetic transfer and what are shared common risk factors engaged in.