Several studies have found that fusobacteria are enriched in human colorectal cancers. To investigate their role in human colorectal cancers, a recent study analysed the microbiome of patient colorectal tissue and metastatic tumours and observed that nearly identical Fusobacterium strains were present in the primary and metastatic tumours, indicating that fusobacteria may migrate with metastatic cancer cells. RNA in situ hybridization revealed that Fusobacterium nucleatum is predominantly localized with cancer cells within metastatic legions. F. nucleatum was also found after engrafting human cancer tissue into mice, and mice that were treated with an antibiotic were found to have less F. nucleatum and had a reduction in cancer cell proliferation and tumour growth, suggesting that antibiotics may be helpful in the treatment of fusobacteria-associated cancers.