Understanding Human Papillomavirus (HPV): 

The Hidden Virus Behind Many Cancers

By Dr. Phon Elin, November 1, 2025

Introduction: What is HPV?

Human Papillomavirus, or HPV, is one of the most common infections in the world. It is a group of more than 200 related viruses, and most people—men and women alike—will get infected with HPV at some point in their lives.

Most infections cause no symptoms and go away on their own. However, some types of HPV can lead to genital warts or even cancers, especially of the cervix, anus, penis, vulva, vagina, and throat.

HPV is so common that about 8 out of 10 sexually active people will get it at least once. The infection often occurs soon after someone becomes sexually active.

How HPV is Transmitted

HPV spreads mainly through skin-to-skin contact, not just through sexual intercourse.

• Sexual transmission: HPV is transmitted through vaginal, anal, or oral sex, and even through intimate skin contact in the genital area.
  Non-sexual routes: It can rarely spread through shared personal items, contaminated surfaces, or from mother to baby during childbirth (leading to a rare condition called recurrent respiratory papillomatosis).
  
  

Fact: You can get HPV even if you have only one sexual partner — and even if that partner shows no signs of infection.

Types of HPV: Low-Risk vs. High-Risk

There are more than 40 types of HPV that affect the genital and throat areas.
They are grouped into:

• Low-risk types – cause warts but not cancer.
  Examples: HPV 6 and HPV 11, which cause about 90% of genital warts.
  
  

• High-risk types – can cause cancer if the infection persists.
  Examples: HPV 16 and HPV 18, responsible for about 70% of cervical cancers worldwide.
  
  

HPV-Related Complications

1. Genital Warts

Soft, flesh-colored bumps that appear on the genital area, anus, or throat. They are not dangerous but can cause discomfort and emotional distress.

2. Cervical Dysplasia and Cancer

Persistent infection with high-risk HPV can cause abnormal changes in the cells of the cervix, known as dysplasia. If untreated, these changes can progress to cervical cancer over many years.

3. Other Cancers Linked to HPV

• Anal cancer

• Penile cancer

• Vulvar and vaginal cancers

• Oropharyngeal cancer (throat, tonsil, and tongue base)
  
  

HPV causes about 5% of all cancers globally—making it one of the most significant infection-related causes of cancer.

How HPV Causes Cancer

When high-risk HPV types (especially 16 and 18) infect the body, they can sometimes integrate their DNA into human cells. This disrupts the normal control of cell growth.

• The viral proteins E6 and E7 inactivate the body’s natural tumor suppressor genes (p53 and Rb).

• When these protective systems fail, cells grow uncontrollably, leading to precancerous lesions and eventually cancer.
  
  

Cervical Cancer: The Best-Known Example

In cervical cancer, persistent infection with HPV damages the cells lining the cervix. Over time, these cells can develop into precancer and then into invasive cancer if not detected and treated early.

Signs, Symptoms, and Screening

Most HPV infections cause no symptoms and clear naturally.
However, some warning signs may include:

• Genital warts

• Abnormal vaginal bleeding or discharge

• Pelvic pain (in advanced cases of cervical cancer)
  
  

Screening Methods

1. Pap Smear (Cytology): Detects abnormal cervical cells.

2. Rapid test (Self Test)

3. HPV Test: Detects the presence of high-risk HPV DNA.
   
   

Women aged 21–65 years should get screened regularly:

• Every 3 years with a Pap smear, or

• Every 5 years with HPV testing (or combined Pap + HPV test).
  
  

Prevention

1. HPV Vaccination

The safest and most effective way to prevent HPV-related diseases is vaccination.

• Gardasil® 9 protects against 9 HPV types (6, 11, 16, 18, 31, 33, 45, 52, and 58).

• Gardasil® protects against four HPV types: 6, 11, 16, and 18.. Types 6 and 11 cause about 90% of genital warts. Types 16 and 18 cause about 70% of cervical cancers and are also linked to other HPV-related cancers.
  
  

Who should get vaccinated:

• Girls and boys aged 9–14 years (before sexual activity begins).
  Catch-up vaccination can be given up to age 26, and in some cases up to age 45 after medical advice.
  
  

How it works: The vaccine trains your immune system to recognize HPV and block infection before it happens. It does not treat existing HPV, so early vaccination is best.

2. Safe Sexual Practices

• Use condoms (though not 100% protective, they reduce risk).

• Limit number of sexual partners.

• Avoid smoking, which increases the risk of cervical cancer.
  
  

3. Regular Screening

Even vaccinated women should continue regular Pap smears or HPV tests, as vaccines do not cover all cancer-causing strains.

Treatment and Management

For Warts

• Topical medicines (imiquimod, podophyllin)

• Cryotherapy (freezing)

• Laser or minor surgery
  
  

For Precancerous Lesions

• LEEP (Loop Electrosurgical Excision Procedure) or Cryotherapy to remove abnormal cells before they become cancerous.
  
  

For HPV-Related Cancers

• Surgery, radiotherapy, and chemotherapy depending on the stage.

• Early detection significantly improves survival.
  
  

Public Health Importance

Globally, HPV causes more than 600,000 new cancer cases every year, with cervical cancer being the most common.
In Cambodia, cervical cancer remains one of the leading causes of cancer deaths among women, mostly due to limited screening and low vaccine coverage.

Expanding HPV vaccination programs and early detection could save thousands of Cambodian women’s lives each year.

Key Takeaways

• HPV is very common, and most infections clear up naturally.

• Some types cause cancer, especially in women’s cervix but also in men.

• HPV vaccines like Gardasil 9 are safe, effective, and life-saving.

• Screening and early treatment prevent cancer before it starts.
  
  

Myth vs. Fact

Myth Fact

“HPV only affects women.” HPV affects both men and women — and can cause cancers in both.

“Only people with many partners get HPV.” Anyone who is sexually active, even once, can get HPV.

“Vaccines are only for teenagers.” Vaccines work best before sexual activity, but adults up to 45 can benefit too.

Conclusion

HPV is preventable. Through vaccination, regular screening, and awareness, we can stop HPV-related diseases and cancers before they begin.

Protect yourself and your loved ones — Get vaccinated. Get screened. Stay informed.

Reference

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