Interestingly, compared to the gut microbiota of tumour-free mice, we found that seven predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways were commonly altered in the gut microbiota of mice for all the end point PCa tumours TRAMP-C2, Pten−/−; Rb1+/+ and Pten−/−; Rb1−/− mice models (Fig. 4f). This evidence concerns the gene RB1 and posterior cortical atrophy.