Banishing HPV-Related Cancers

The human papillomavirus (HPV) is more menacing than previously believed. In addition to causing 99 percent of cervical cancers, the virus is linked to some types of oral and other genital malignancies.

And while two vaccines are available to prevent HPV infection, there are no vaccines to treat the disease once it appears. That could be changing.

Researchers at the Moffitt Cancer Center in Tampa, Florida have created and tested a synthetic vaccine that kills HPV-derived cancers.

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"Vaccines for cancer can be good alternatives to conventional therapies that result in serious side effects and are rarely effective against advanced disease," said Esteban Celis, MD, PhD, senior member and professor in Moffitt's Immunology Program.

Dr. Celis worked with Kelly Barrios-Marrugo, PhD, of the University of South Florida College of Medicine's Molecular Medicine program, to design a vaccination strategy called TriVax-HPV.

Trivax-HPV helps generate soldier T-cells that hone in on and kill proteins seen in tumors.

The viral proteins being targeted are HPV15-E6 and E7, which the researchers describe as "ideal candidates" to trigger the immune system to fight, without the response going overboard.

To test the strategy, mice with HPV16-induced tumors were given the TriVax which contained a tiny synthetic fragment (peptide) of the E7 protein.

The vaccine "induced tumor clearance in 100 percent of the treated mice" while the HPV tumors in untreated mice grew rapidly.

While optimistic, Barrios-Marrugo is also cautious. "Although the magnitude of the T-cell responses achieved with TriVax in mice is impressive, we do not know whether similar effects can be accomplished in humans."

Current treatments for cervical cancer, which is widespread in developing countries, can be very toxic, with a 10 percent recurrence rate.

Additionally, women in these areas don't have the benefit of the preventive vaccines and will continue to be at high risk.

"We believe that these studies may help to launch more effective and less invasive therapeutic vaccines for HPV-caused malignancies," concluded the authors.

This research was published in a recent issue Cancer Immunology, Immunotherapy.

The study was supported by National Institutes of Health grants.