How The New Cervical Cancer Vaccine Works

Cervical cancer is the growth of malignant tumor cells in the cervix resulting in death. The 2003 World Cancer Report says that an estimated 500,000 women in developing countries are diagnosed with the disease every year – of which 250,000 die. Cervical cancer is caused by the human papillomavirus (HPV), a common form of sexually transmitted infection. HPV looks like a golfball under a microscope. Its core infectious substance is protected by a hard shell made of L1 protein. There are about 100 different varieties of HPV. Most of them show no symptoms and are generally harmless. But HPV 16 and HPV 18 are particularly deadly. These two strains are the cause of 70% of all cervical cancer cases. Infection starts when HPV penetrates the cervical lining at the base of the uterus and attaches itself to the epithelial cells. Then the L1 shell releases the infectious genes from inside the HPV into the body. These include the viral genes E6 and E7 that neutralizes the body’s ability to suppress invading cells. The lesions become fatal after about 12 to 15 years. Left untreated, cervical cancer causes excruciating pain until “women bleed to death,” according to Dr. Diane Harper, an HPV-vaccine investigator from Dartmouth Medical School. Early detection can spell the difference between life and death. Abnormal cell growth can be tracked by regular Pap smear screenings. Here’s good news: a breakthrough HPV vaccine is now available. “This is the first vaccine designed to strike at the root of a cancer,” according to Dr. Martin Murphy, executive editor of The Oncologist. “Boy, is this a new era!” There are actually two vaccines: from GlaxoSmithKline (GSK) and Merck, Sharp and Dohme (Merck). Clinical trials showed nearly 100% protection against HPV 16 and HPV 18. Participants are showing consistently high levels of antibodies even 4 ½ years after inoculation. “We’re very encouraged,” reported Dr. Gary Dubin, head of clinical development at GSK. The vaccine was first discovered when the L1 protein was isolated in a petri dish. By itself, the L1 transformed itself into a “virus-like particle” but with “none of the bad stuff inside,” explains Dr. Eliav Barr, head of the HPV-vaccine program at Merck. The new HPV vaccine is essentially an empty L1 shell. Once injected, it will trigger the immune system to produce antibodies to destroy the bogus virus. “If actual HPV appears in the body later, the antibodies cling to it, interfering with its ability both to bind to the cell and to release its genetic material,” according to Dr. Doug Lowy from the National Cancer Institute of the U.S. National Institutes of Health. More good news: the Bill and Melinda Gates Foundation has just granted $3.5 million for the development of “an inexpensive vaccine that would protect against HPV and eradicate the virus in women who are already infected,” reported Claudia Kalb and Karen Springen in the May 8, 2006 issue of Newsweek. “And they hope to make the vaccine out of powder so that it doesn’t need refrigeration and can be easily transported to remote villages.” This pioneering study can save the lives of millions. “It’s never been done before,” says Dr. Robert Garcea of the University of Colorado, recipient of the Gates Foundation’s Grand Challenges in Global Health Award. “If it works, it’ll be great.” The Department of Health recommends vaccinating girls as early as 9 years old, or even before sexual maturity. Photo courtesy of Stuff. This story originally appeared in Philippine Graphic Your comments and links are welcome