Link identified between cervical microbiome and cancer.
Cervical cancer is a cancer that develops at the entrance of a woman’s womb from the vagina, otherwise known as the cervix, which mainly affects sexually active women aged between 30 and 45. According to a 2012 study, Human papillomavirus (HPV) is responsible for 99% of all cervical cancer cases. However, multiple studies show an increase in HPV detection in cervical intraepithelial neoplasms in individuals with depleted immune cell numbers, therefore, the cervical immune microenvironment may be a factor in suppression of cervical cancer. Now, a study from researchers led by University of Nebraska–Lincoln shows a significant association between the composition of a woman’s cervical microbiome and the presence of pre-cancerous lesions on her cervix. The teams state that their data suggests a greater influence of the bacterial microbiota on the outcome of HPV infection than previously thought. The opensource study is published in the journal mBio.
Previous studies show cervical cancer is a devastating problem in Sub-Saharan Africa, where 8% of the world’s women older than 15 account for 14% of the cervical cancer cases and 18% of the cervical cancer deaths; with the burden of HPV-associated dysplasias in sub-Saharan Africa is influenced by human immunodeficiency virus (HIV), an autoimmune disease. However, the role of the cervical bacterial microbiome in cervical cancer is not clear. The current study collects cervical cytobrush samples from 144 Tanzanian women and performs deep sequencing of bacterial 16S rRNA genes, commonly used in the study of bacterial phylogeny and taxonomy, to investigate this link.
The current study utilises deep sequencing, a way to genetically identify thousands of bacterial families all at once, to identify the bacteria present in samples obtained from 144 Tanzanian women who underwent cervical cancer screenings between March 2015 and February 2016. Results show that 126 women tested positive for Human HPV, 41 women tested positive for HIV, and 50 women were diagnosed with high-grade pre-cancerous lesions. Data findings show 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.
Results show that HIV-positive patients had greater bacterial richness than HIV-negative patients. Data findings show that Mycoplasma bacteria, specifically, may help promote the growth of HPV-related lesions. The lab state in particular, an abundance of Lactobacillus crispatus shows an inverse relationship with detectable or symptomatic HIV, HPV, or herpesvirus infection. They go on to conclude this suggests that other cervicovaginal microbes may be important in preventing or enhancing the acquisition and pathogenesis of such infections.
The team surmise that their data shows Mycoplasma bacteria contributes to a cervical microbiome status which promotes HPV-related cervical lesions. For the future, the researchers state that although more research is needed, the findings suggest that one day cervical microbiota could be used for cancer screening and diagnosis, or perhaps cancer could be treated or prevented with probiotics or antibiotics.
Source: University of Nebraska–Lincoln