Researchers find presence of “high-grade” precancerous lesions caused by human papillomavirus (HPV) associated with “richness” of cervical bacteria

Could bacteria residing in the cervix of women be useful in screening for cervical cancer? That’s what a study into the connection between human papillomavirus (HPV) infections and the human immunodeficiency virus (HIV) conducted by researchers at the University of Nebraska-Lincoln (UNL) and the Ocean Road Cancer Institute in Tanzania, seems to suggest.

Additional studies will be needed, but if the apparent causality proves out, it could lead to new clinical laboratory biomarkers to help determine women’s risk for developing cervical cancer.

The researchers published the results of their study in mBio, an open-access journal of the American Society for Microbiology.

New Cervical Cancer Screening Biomarker for Clinical Labs, Pathology Labs?

Human gut bacteria (aka, gastrointestinal microbiota, a component of human microbiome) has been at the center of many revolutionary studies in past years, and has been the subject of many Dark Daily e-briefings. But this may be the first instance of the cervical microbiome being thought of as a potential biomarker in cancer screening.

To perform the research, the scientists obtained tissue samples taken from cervical lesions of 144 women who had undergone cervical cancer screenings in various locations throughout Tanzania between March 2015 and February 2016. The researchers then used a technique known as “deep sequencing” to sequence 16 Ribonucleic acid (RNA) genes from the samples.

One hundred and twenty-six of the women tested positive for HPV and 41 tested positive for HIV. In addition, 50 of the women were diagnosed with high-grade lesions that were likely to become cancerous.

And here is where the researchers made their discovery. They found that the “women with the high-grade lesions had a more abundant and diverse microbial mix in their cervical microbiomes than women who had no lesions or less serious lesions,” noted a UNL news release.  

“There are certain families of bacteria that appear to be associated with the higher grades of precancerous lesions,” Lead Author Peter Angeletti, PhD, Associate Professor, Biological Sciences, University of Nebraska-Lincoln, noted in the news release. “What we know so far is that there is a relationship between the virus commonly associated with cervical cancer and the microbiome.”

Peter Angeletti, PhD
Peter Angeletti, Associate Professor, School of Biological Sciences, and Cameron Klein, graduate student in virology, have discovered a link between the HPV (Human papillomavirus) virus and how various bacteria effect it’s growth. February 18, 2019. Photo by Craig Chandler / University Communication

The researchers found that a certain group of bacteria known as Mycoplasma may play a role in the growth of HPV-related cervical lesions. According to UNL, this type of bacteria is known to cause illnesses such as:

It also can be sexually transmitted.

The World Cancer Research Fund (WCRF) lists cervical cancer as the fourth most common cancer occurring in women worldwide and the eighth most common cancer overall.

Cervical Cancer Rates in Sub-Saharan Africa

Nineteen of the top 20 countries for cervical cancer are located in Sub-Saharan Africa. The Centers for Disease Control and Prevention (CDC) reports that about one in four individuals in the US—nearly 80-million individuals—are currently infected with HPV. 

At one time, cervical cancer was the leading cause of cancer deaths for women in the US. According to the CDC, there were 12,845 new cases of cervical cancer reported in the US in 2015, and 4,175 women died of the disease that year. Those numbers correlate to eight new cervical cancers reported per 100,000 women and two cancer deaths per 100,000 women in the US. 

By contrast, in 2018, for every 100,000 women there were 75.3 new cervical cancer cases reported in Swaziland, the country with the highest rates of the disease, according to WCRF statistics.

There were more than 500,000 new cases of cervical cancer reported worldwide in 2018.

However, new cases of the disease and deaths from cervical cancer have decreased significantly since regular Pap smears became a standard test for women in the US.

The findings of this study indicate additional examination of cervical microbiome could result in useful clinical laboratory data for developing diagnostic tests and possible new treatments for cervical cancer.

—JP Schlingman

Related Information:

Cervical Microbiome Could Help Predict Cancer Risk

Relationship between the Cervical Microbiome, HIV Status, and Precancerous Lesions

Link between Cervical Microbiome and Cancer Discovered

Cervical Microbiome May Promote Cancer

Genomic Study Reveals Role of Human Papillomavirus in Cervical Cancer and Identifies Novel Therapeutic Targets for the Disease

Is New Cervical Cancer Test Better Than a Pap Smear?