Vaginal Microbiome and Its Relationship to Cervical Cancer

It’s common not to think about cervical health outside your routine gynecologist appointment. The cervix is an internal organ that connects the bottom of the uterus to the vagina, so it’s out of sight and often out of mind. However, cervical cancer is a serious issue that causes an estimated 300,000 deaths worldwide each year. It’s the fourth most prevalent cancer for women, with around 570,000 new cases diagnosed annually [1].

Healthcare providers frequently use pap smears to screen women for cervical cancer and catch abnormal cells before they develop into malignant tumors [2]. But new research suggests that maintaining the health of your vaginal microbiome can also help fight and potentially even prevent cervical cancer.

Research suggests that maintaining a healthy vaginal microbiome is the first line of defense against cervical cancer [6].

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Understanding HPV: The Root Cause of Cervical Cancer

Before we dive into the association between cervical cancer and microbiota, it’s important to understand how this disease develops. Human papillomavirus (HPV) is a group of viruses that cause approximately 99.7% of cervical cancer cases. More than 70% of sexually active men and women will get infected by HPV during their lifetime [2]. High-risk HPV is asymptomatic, so you won’t know if you have it unless you get tested [3].

Around 90% of HPV infections go away without treatment within two years, and many people with HPV never develop cancer [2]. However, this condition can have lasting effects on many parts of your reproductive system, including your cervical tissues and vaginal microbiome. The progression from HPV to cervical cancer varies but typically occurs over 10 to 12 years and follows these stages [4]:

• Infection of the Cervix: The virus infects cells in the membranes lining the inner canal and outer surface of the cervix.
• Cell Disruption: The HPV infection disrupts the normal growth cycle of cervical cells and alters their genetic makeup. Some of these cells start dividing uncontrollably.
• Abnormal Cell Growth: Some of the newly infected cells may have abnormalities. Over time, these abnormal cells can transform into precancerous lesions and then progress into cervical cancer.

The Relationship Between HPV, Cervical Cancer, and the Vaginal Microbiome

Along with infecting cells, HPV wreaks havoc on your cervicovaginal microbiota. Studies indicate that HIV-positive women have different vaginal microbiota than women without this disease. That’s because this virus destroys the helpful bacteria in your reproductive system and allows abnormal flora to colonize it. As a result, your vaginal microecosystem can get thrown out of balance [5].

This disruption can have serious implications for your health. Women with healthy vaginal flora produce Lactobacillus, a genus of helpful bacteria. Lactobacillus fights malignant cells by [5]:

• Triggering the immune system to release antitumor compounds, such as extracellular polysaccharides
• Preventing aggressive pathogenic bacteria from adhering to vaginal tissues
• Increasing HPV clearance
• Improving the function of natural killer cells, a kind of white blood cell

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HPV reduces the number of Lactobacillus and other good bacteria in your reproductive tract, weakening your body’s natural defense system. This disruption of your vaginal microbiota can leave you more vulnerable to cervical cancer and other disorders [5].

Vaginal flora, which comprises beneficial bacteria, not only supports vaginal health but also combats pathogens responsible for infections such as bacterial vaginosis, inhibits the growth of malignant cells, and can even target and destroy cervical cancer cells [5].