Exploring the Microbiome of Cervical Cancer through Transkingdom Networks

Cervical cancer is the fourth most common cancer in women worldwide. Recently the role of microbiota in some types of cancer has been shown. Therefore, to understand if microbes contribute in any way to the development and progress of cervical cancer we investigated the cervical microbiome via analysis of 16S rRNA sequencing data. Using qPCR we detected bacterial DNA in 118 out of 133 samples of cervical carcinoma. However, 16s library preparation and sequencing was possible for only 58 samples with higher amounts of bacterial DNA. After matching our results with the Human Microbiome Project,  we observed that cancer samples compositionally represent a very tight cluster with its closest neighbors in principle coordinate analysis being samples from the vagina, stool, and skin.  Overall, the alpha diversity of cervical cancer communities was quite low (Shannon index 3.88) compared to the healthy microbiome of other body sites. Furthermore, the most abundant taxa in these samples were of phyla Bacteroidetes (39%),  Firmicutes (25%), Fusobacteria (14%), and Proteobacteria (9%). To get a better understanding of the structure of cancer bacterial communities, we have reconstructed a microbial covariation network. This work presents the previously unexplored microbiome of invasive cervical cancer. Despite its low diversity, the cervical cancer microbiome is a complex structure not limited to a few microbes. The analysis of transkingdom interactions are underway to reveal the place of bacteria in tumor, host, and HPV interactions for development of cervical cancer.