Background: There is a close link between Fusobacterium nucleatum and colorectal cancer (CRC) tumorigenesis and chemoresistance. However, the genetic characteristics and clinical significance of CRC related with F. nucleatum remains unclear. This study evaluated the relationship between F. nucleatum, pathway mutation, and patient prognosis.
Methods: Fusobacterium nucleatum amount in the tumor tissue and adjacent normal tissue were measured by quantitative polymerase chain reaction in adjuvant (N = 128) and metastatic (N = 118) cohorts. Patients were divided into binary (F. nucleatum-high and F. nucleatum-low) according to F. nucleatum amount. Targeted next-generation sequencing of 40 genes included in the 5 critical pathways (WNT, P53, RTK-RAS, PI3 K, and TGF-β) was performed in the adjuvant cohort.
Results: Patients with MSI-H and CIMP-H had higher amount of F. nucleatum in tumor tissue. Fusobacterium nucleatum-high patients had higher rates of transition mutation and C to T (G to A) nucleotide change regardless of MSI status. In addition, mutation rate of AMER1 and ATM genes, and TGF-β pathway was higher in F. nucleatum-high patients. Fusobacterium nucleatum-high was associated with poor overall survival (OS) in the palliative cohort (26.4 vs. 30.7 months, p = 0.042). Multivariate analysis revealed F. nucleatum-high as an independent negative prognostic factor for OS [adjusted hazard ratio of 1.69 (95% confidence interval 1.04-2.75), p = 0.034]. However, F. nucleatum amount was not associated with recurrence in the adjuvant cohort.
Conclusions: F. nucleatum-high was associated with poor survival in metastatic CRC. In addition, we identified mutational characteristics of colorectal cancer according to F. nucleatum amount.