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Gone viral

How a seemingly innocuous virus causes one of the most deadly malignancies.

By Adrienne Dy, M.D.

MARCH 2013

It’s a sad and unfortunate state we’re in right now, where everyone knows someone, or someone’s someone, with cancer. The Big C is so big, it could be called the great modern plague.

Cancer contagion?

But is cancer contagious? Not at all. Cancer is characterized by the uncontrollable spread of abnormal cells that take over organs and shut down body systems. Though its exact mechanisms have yet to be named, faulty genes, dangerous exposures and an unhealthy lifestyle are the perpetrators identified so far. Take note: Infection is nowhere on that list. But there are a handful of cancers borne of something spread from person to person—viruses.

• Hepatitis viruses cause liver infections and lay the foundations for liver cancer.

• The Epstein-Barr virus has been linked to nose and throat cancers, as well as some lymphomas.

• The human herpes virus can cause a sarcoma in the setting of a weak immune system.

• The human papillomavirus (HPV) causes cancer in the cervix—as well as in the anus, vulva, vagina, penis, throat and oral cavity.

Of these, HPV is of great concern, accounting for roughly five percent of cancers worldwide—hence, it’s one of the deadliest malignancies.

Voracious virus

In a lecture sponsored by the pharmaceutical Merck Sharp & Dohme, Margaret Stanley, Ph.D., professor of epithelial biology and director of the research department of pathology in the University of Cambridge in the U.K., demystified HPV and its dangers.

Prof. Stanley’s slide on HPV was almost beautiful—the perfect, pinkish sphere of a virus, dotted on the surface with delicate-looking rosettes, looked nothing like a killer. But the numbers were ugly—there are over a hundred HPV strains, of which about 30 to 40 infect the genital area of humans, and 15 cause cancer.

Viruses are described as half-alive or “organisms at the edge of life,” because they lack cell structure and cannot replicate on their own. These infectious agents are therefore quite the smooth operators, latching on to host cells and manipulating their machinery to survive and spread.

HPV thrives inside the cells of the skin. They take over in what starts as dysplasia or pre-cancerous lesions, which over time—possibly years—become full-blown malignancies.

Warts and worse

HPV can be classified into low- and high-risk types. Genital warts are caused by low-risk HPV 6 and 11. These appear as flesh-colored lesions that can be raised, flat, or cauliflower-like. Men aren’t spared; aside from the vagina, vulva and cervix, the penis is also a common site. And the groin and anal area aren’t the only vulnerable areas: Genital warts can also occur on the lips, oral cavity and throat. This is a benign but troublesome condition—too-easily spread, sometimes with mild itching, dampness and discharge.

High-risk HPVs cause virtually all cervical cancers. They include types 16 and 18, which together are responsible for 70 percent of cervical malignancies. Prof. Stanley says there are approximately half a million new cases of cervical cancer each year, resulting in a quarter-million deaths. Add penile, vaginal, vulval, anal, pharyngeal and oral cavity cancers to its resume of diseases, and it becomes clear—HPV has become a major carcinogen.

Let’s talk about sex

Sex plays a big role in the spread of this infectious agent. Risk of infection increases with sexual intercourse early in life; multiple sexual partners; and high-risk sexual activities.

How then can HPV be contained? The obvious answer is to reduce risk factors. It’s a huge incentive for monogamy, but it’s prudent to take other precautions as well. For cervical cancer, in particular, women have several options available.

Short for Papanicolaou test, the pap smear is an effective screening tool for cervical cancer. It involves taking a swab of cervical mucus and studying it for precancerous or cancerous cells. Generally recommended at age 21 and every two to three years thereafter, it catches any chance of malignancy early, for swift and definitive management at the slightest hint of danger.

Beating an opponent like HPV may require more offense than defense, though.

Three shots to deliverance

HPV-related cancers are almost preventable through immunization. The key to creating an HPV vaccine lies in the virus’ rosettes, which are actually proteins that our immune systems can recognize. These proteins are reassembled into virus-like particles (VLPs) that closely resemble the real thing. Three shots of either the bivalent or quadrivalent vaccine, with two and four VLPs respectively, administered two and six months apart, giving our body’s defenses a chance to create antibodies, ready to ward off the real thing when it strikes.

Since the advent of HPV vaccines, the possibility on turning the tables on this battle has grown considerably. Prof. Stanley reports in the U.K. and Australia, reductions in high grade dysplasias as large as 50 percent have been observed, less than three years after the introduction of a nationwide HPV vaccination program. There was also a 90 percent decline in genital wart cases in those given vaccines with VLPs for HPV 6 and 11. Better still, though only girls were given the vaccines, it afforded protection to their male partners as well.

It may take a while before the Philippines institutes its own HPV vaccination program. At the moment, it’s up to the individual—male or female—to seek out protection from the deadly virus.

Find more answers to your HPV vaccine questions in the March issue of HealthToday, out now in newsstands and bookstores.

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