Viruses recruited as killers of tumors?

Transmission electron micrograph of herpes sim...

Transmission electron micrograph of herpes simplex virus Transmission electron micrograph of herpes simplex virus. Some nucleocapsids are empty, as shown by penetration of electron-dense stain. (Photo credit: Wikipedia)

Afolake Ogunfuwa (3 PM Micro) found this article from the New York Times, describing a potential anti-tumor treatment. Long time readers may recall how microbiology can be used for non-traditional, thinking outside the box, approaches in cancer therapy. Here is Lake’s summary:

The caption from the article on the New York Times website caught my attention: “viruses recruited as killers of tumors”. This sounded like science fiction, but my current adventure into the mysteries of microbiology, affirm that medical science has evolved in amazing ways over the last century. For example the introduction of vaccines which has eradicated some deadly diseases that previously claimed countless lives. Research that is continually done in various centers around the world, give support to the idea that new or improved treatment modalities are being or will be perfected in the not too far future. The many struggles of people with cancer are not foreign to me, and any respite these brave souls get is worth every investment by society.

The article started with the heartbreaking experience of a child that battled a form of cancer about 60 years ago. The leukemia was gradually killing this child until a viral illness called chickenpox brought the leukemia to its knees. This miracle was short-lived because upon recovery from the viral illness, the child lost its battle with the cancer. The experiences of many with cancer prior to this period were not different from the outcome in this child; they died with little hope! Probably, this little life that was lost sparked the idea: help for cancer sufferers might be found in viruses. Apparently doctors observed that other cancer patients enjoyed brief remissions in their experiences with cancer.

The article mentioned that since doctors found that common viruses attack tumor cells, attempts to turn this into beneficial treatment has been challenging. Early attempts over 100 years ago arose from the observation that women with cervical cancer got temporary relief when they were vaccinated with the rabies virus. The efforts of doctors to reproduce these results in cancer patients by actively infecting them with various viruses were largely a failure. As a result, viral cancer killers as a treatment method were abandoned until about 20 years ago when the separate works of Dr Roizman and Dr. Martuza were published.

Dr Martuza chose the herpes simplex virus (HSV-1) because of its large genetic material and removed some genes in an effort to make the virus less virulent. These modified viruses were injected into mice with brain cancer which promptly went into remission but later died from the encephalitis that followed. The year before, Dr Roizman believed he had found the master gene in the herpes virus that can be removed to make the virus avirulent. These modified viruses only slowed tumor growth. Further investigation by other researchers found ways for these modified viruses to evade destruction by the body’s immune system, making them more potent in fighting cancer than Dr Roizman’s earlier viruses. These treatments are promising when compared to standard cancer treatment because their efficacy does not seem to reduce with time. Recently, advanced liver cancer, which is the third leading cause of cancer death world-wide, is being tested against the viral vaccine for small pox. Administering high dose of the viral vaccine (JX-594) increased the survival rate of patients compared to using the small dose.

In conclusion, the obvious fact from the article is that nature is lending a helping hand in the fight against human cancer in the form of viruses. These viral treatment methods may not prove to extend life, but they have been shown to improve the quality of life in those final moments in many cancer patients. When the many side effects of currently used, powerful anti-cancer chemical agents can be eliminated by the full use of viral caner killing agents in the future, many may be able to die with dignity.

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About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on April 19, 2013, in Guest Post. Bookmark the permalink. Comments Off on Viruses recruited as killers of tumors?.

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