The Gut Microbiome in Aging and Ovarian Cancer

Abstract

The gut microbiome changes with age and affects regions beyond the gut, including the ovarian cancer tumor microenvironment. In this review summarizing the literature on the gut microbiome in ovarian cancer and in aging, we note trends in the microbiota composition common to both phenomena and trends that are distinctly opposite. Both ovarian cancer and aging are characterized by an increase in proinflammatory bacterial species, particularly those belonging to phylum Proteobacteria and genus Escherichia, and a decrease in short chain fatty acid producers, particularly those in Clostridium cluster XIVa (family Lachnospiraceae) and the Actinobacteria genus Bifidobacterium. However, while beneficial bacteria from family Porphyromonadaceae and genus Akkermansia tend to increase with normal, healthy aging, these bacteria tend to decrease in ovarian cancer, similar to what is observed in obesity or unhealthy aging. We also note a lack in the current literature of research demonstrating causal relationships between the gut microbiome and ovarian cancer outcomes and research on the gut microbiome in ovarian cancer in the context of aging, both of which could lead to improvements to ovarian cancer diagnosis and treatment.

Keywords: Ovarian cancer; aging; gut microbiome.

Figure 1.

The alpha diversity of the gut microbiome can vary in richness, evenness, and phylogenetic diversity. (a) The low richness upper sample contains only one species while the high richness lower sample contains many species. (b) The less even upper sample contains more light blue bacilli than any other species while the more even lower sample contains roughly equal numbers of each species. (c) The low phylogenetic diversity upper sample contains many phylogenetically related blue bacilli while the high phylogenetic diversity lower panel contains species from many branches of the phylogenetic tree.

Figure 2.

Venn diagram of taxa affected by ovarian cancer. Arrows indicate the direction of change for grouped taxa or features in the indicated situation. Taxa in brackets are neither increased nor decreased but are added to clarify the classification of lower taxa.

Figure 3.

Venn diagram of taxa affected by aging and ovarian cancer. Arrows indicate the direction of change for grouped taxa or features in the indicated situation. Taxa in brackets are neither increased nor decreased but are added to clarify the classification of lower taxa.