Fusobacterium Nucleatum Is a Risk Factor for Metastatic Colorectal Cancer.

OBJECTIVE: Increasing evidence has indicated that there is a correlation between Fusobacterium nucleatum (F. nucleatum) abundance and poor prognosis of colorectal cancer (CRC). Furthermore, tumor metastasis plays a decisive role in the prognosis of CRC patients. Therefore, it was hypothesized that the abundance of F. nucleatum in CRC tissues affects the tumor metastasis. METHODS: In the present study, F. nucleatum DNA obtained from 141 resected CRC samples was quantified by qPCR to determine whether there were differences in F. nucleatum abundance between groups with and without CRC metastasis. RESULTS: The results revealed that F. nucleatum was more abundant in CRC patients with metastasis, and CRC tissues enriched with F. nucleatum had a higher risk of lymph node metastasis and distant metastasis. The receiver operating characteristic curve indicated that F. nucleatum in CRC tissues could be used as an indicator for CRC metastasis, to some extent. Furthermore, the in vitro experiments (electron microscopy, and migration and invasion trials) revealed that F. nucleatum was a highly invasive bacterial strain, and could significantly enhance the invasion and migration capacity of SW480 and SW620 cells. In addition, a meta-analysis comprehensively indicated a slight correlation between F. nucleatum abundance and advanced CRC stage (RR=1.17, 95% CI: 1.00-1.37, P=0.04, random effect). CONCLUSION: There is a correlation between F. nucleatum abundance and CRC metastasis, and F. nucleatum may serve as a metastasis biomarker for CRC patients.