Herpes: The virus we may not want to hate so much

Magdalena Angelova, Ph.D. from the laboratory of David Knipe, Ph.D. at Harvard Medical School
Magdalena Angelova, Ph.D. from the laboratory of David Knipe, Ph.D. at Harvard Medical School

For decades we have known that microbes cause many diseases known to plague us as humans (did you see what I did there?). It’s easy to identify the microbes that cause disease but it’s harder to identify the microbes that do not harm us or more interestingly the ones that actually benefit our survival. Now some resourceful folks have taken microbes that cause disease and turned them into disease fighting weapons.

It’s easy to use the analogy of war for microbes that cause disease. There is an enemy, the microbe, and an army fighting to protect you, your immune system. Now we may have to adjust our thinking. Last week the FDA approved a modified herpes virus to add to our arsenal in the fight against cancer, specifically melanoma. I know what you’re thinking.

Herpes, Ew.

I hate to break this to you but you probably already have it. The kind that causes cold sores is very common, over 60% of people already have it even if you’ve never had a cold sore.

Sorry to bring you down.

I am a virologist and until very recently I studied herpes viruses. I find herpes viruses to be a little complicated for my taste. In my opinion, viruses are supposed to be simple and efficient. They make only what they need and steal the rest.

However, the good thing about a complicated virus is there’s more room to play around with it. You can add and delete things like choosing accessories for your new car. A herpes virus, dubbed Imlygic, has recently been customized to treat cancer and has been approved for the treatment of melanoma. Imlygic has been customized to replicate in tumor cells and to produce a signal to stimulate the immune system to attack the cancer cells. In this way the virus and the immune system work together to attack cancer cells. I know what you’re probably thinking. “Yay herpes, you go girl.” This type of treatment is called oncolytic virotherapy, which roughly translates into cancer-destroying virus treatment.

The field of oncolytic virotherapy has actually been around since the 1950s and is now gaining more public attention. Interestingly, the potential for viruses to be used as cancer therapy was recognized over a century ago. In the late 1800s one doctor noted that a leukemia patient went into remission after being infected by the influenza virus1.

Currently, there are over 25 clinical trials involving oncolytic virotherapy that are recruiting, active, or completed so you should expect to see more exciting new from this field in treating many different types of cancer.

I don’t want to confuse the matter further by as an interesting side note, about 20% of all cancer is actually caused by viruses2. Eventually we could be using engineered viruses to fight cancer that was caused by a virus in the first place. That’s so meta.

If you’d like to learn, more check out these interesting articles:

And if you’re fluent in biology*: (*I maintain that biology is a foreign language)

1. G. Dock, “The influence of complicating diseases upon leukemia,” Am J Med Sci, 127:563-92, 1904.
2. McLaughlin-Drubin, Margaret E., and Karl Munger. “Viruses Associated with Human Cancer.” Biochimica et biophysica acta 1782.3 (2008): 127–150. PMC. Web. 5 Nov. 2015.

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