Recently a friend passed on some studies looking at the overall rate of occurrence of HPV, Human Papilloma Virus, in lung cancers. Basically what they found was that depending on where on the planet your looking the rate ranges from 15-35% of lung cancers are infected with that virus. Given that lung cancer is one of the leading causes of cancer deaths it sounds like a good thing to know about.
Now HPV is actually a family of viruses that cause warts. And it’s a big family of viruses; over 100 different types of HPV have been identified. Plantar warts most likely caused by HPV-1. Warts of your palms, HPV-2. Genital warts, HPV-6, -11, -42, -44. Cervical cancer, HPV-16 and -18 are the main culprits. See the interesting thing about papiloma viruses, is that they are incredibly site specific. The same virus that infects your hands isn’t going to be able to infect your juicy bits.
But did you notice that cervical cancer was in that list? Yeah, we know what cause the vast majority of cervical cancers. The same virus that causes anal cancers. Some other genital cancers are also linked to HPV, but not with the same degree of specificity. Someone got the idea to start looking for HPV in head and neck cancers, probably because sometimes we put other people’s genitals, which may be infected with HPV, in our mouths. And lo and behold there are group of cancers in the head and neck that behave differently then other head and neck cancers, in terms of treatment response, location and prognosis, and they are infected with HPV.
And now it’s been linked to some forms of lung cancer.
And before you run out in terror regarding the wart cancerous death rest assured that the body actually does a pretty good jump of cleaning up HPV infection over a few years. After two years, 70% of HPV infections are gone from the body. Which leaves 30% of the infections persisting for longer.
A few years ago the Gardasil vaccine came out for HPV-16 and -18. I’m going to avoid the debate around vaccines for now, and just say that I believe preventing infection is more effective than treating infection. But given our current attitudes towards vaccination and the hundreds of types of HPV, a vaccine probably isn’t going to solve the problem of what to do about a known cause of cancers. Even if it was 100% effective, it’s kind of like taking the biggest piranha out of a tank of piranhas. I’m still not willing to stick my face in it.
In the next week or so, I’ll look at some of the treatments for HPV infection.