An imbalance in the vaginal microbiome linked to gynecological cancers

Cervical, ovarian and endometrial cancers are characterized by a unique vaginal microbial signature. A simple vaginal sample could thus detect the presence of cancer cells early, according to a study that appeared in Open Life Sciences.Gynecological cancers are often diagnosed at an advanced stage, complicating treatment and prognosis. Researchers therefore suggest including the composition of the vaginal microbiota in a screening program to identify women at risk. In patients with one of the three most prevalent gynecological cancers, greater microbial diversity and an abundance of pathogenic bacteria were observed. More specifically, this group showed a reduction in the abundance of Firmicutes and Lactobacillus and a higher proportion of Bacteroidetes, Proteobacteria, Prevotella, Streptococcus and Anaerococcus. “Our samples were composed of individuals from different countries, different ethnic groups, with varying lifestyles and diverse physical conditions,” explained the authors of the study. "Due to the diversity of our samples, our results are therefore generalizable and representative of a wide range of people."A cause and effect link to be determinedIn addition to facilitating diagnosis, the study of vaginal microbial dynamics can explain resistance to certain anticancer therapies. As is the case for the intestinal microbiota, bacteria in the vagina influence the effectiveness of treatments. In the case of locally advanced cervical cancer, patients with an abundance of Bacteroides respond less well to neoadjuvant platinum-based chemotherapy. As for the vaginal microbiota dominated by Escherichia, it may cause chemoresistance in the treatment of ovarian cancer.While the correlation has not yet been established, certain mechanisms suggest a link between cancer and the vaginal microbiome.For example, it is already recognized that low bacterial diversity and high Lactobacillus levels are associated with a lower risk of HPV infection, cervical dysplasia and cervical cancer. Bacteria from the lactobacilli family exert a protective effect by producing lactic acid, which creates an environment hostile to pathogens. Their reduction leads to an imbalance in the vaginal flora and generates an inflammatory environment. In 2022, preliminary results suggested that this inflammation is probably crucial in the progression of preneoplastic lesions towards cervical cancer.“The discovery of this microbial signature will be useful in determining the unique interactions between the host and certain bacteria or metabolites in order to elucidate the pathogenesis of this type of cancer,” concluded Junnan Xu, researcher at the Cancer Hospital of the Dalian University of Technology in China, and first author of the study.

An imbalance in the vaginal microbiome linked to gynecological cancers

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