Objective  To evaluate the prognostic impact of abundance of Fusobacterium nucleatum (Fn) in the tumor tissues in stage Ⅱ colorectal cancer (CRC) patients.

Methods  Tumor specimen of 151 CRC stage Ⅱ patients receiving surgical treatment at Affiliated Hospital of Yangzhou University between January 2013 and December 2018 were collected. The relative levels of Fn gene in the CRC tissues were detected using quantitative real-time polymerase chain reaction, and were divided into highFn level group and low Fn abundance group using the median method. The chi-square test was used to analyze the correlation between Fn abundance and clinical features. The Kaplan-Meier survival analysis was used to clarify the impacts of Fn abundance on the cancer-specific survival (CSS) and disease-free survival (DFS) of the patients. The univariate and multivariate analysis based on the Cox proportional hazard model was used to identify whether Fn abundance was an independent prognostic factor.

Results  No significant correlation was observed between Fn abundance in the CRC tissues and any of clinical features (P>0.05). In the stage Ⅱ CRC patients, Fn abundance was negatively correlated with the CSS and DFS (P=0.01). The univariate and multivariate analysis revealed Fn abundance was an independent unfavorable factor affecting CSS and DFS (P < 0.05). Subgroup analysis showed that Fn abundance had no relation with the CSS or DFS of low-risk stage Ⅱ patients (P=0.22, 0.47), but was negatively correlated with that of high-risk stage Ⅱ patients (P < 0.01). The univariate and multivariate analysis revealed Fn abundance was an independent factor affecting CSS and DFS in the high-risk stage Ⅱ CRC patients.

Conclusion  Fn abundance in the CRC tissues is identified as an independent influencing factor for high-risk stage Ⅱ CRC patients. Targeting Fn may be a novel strategy to the prevent postoperative recurrence and progression of CRC.