Intratumoral Levels And Clinical Significance Of Fusobacterium Nucleatum In Cervical Carcinoma

Background The global morbidity and mortality of cervical cancer remained stubbornly high.About 10% of newly diagnosed cervical cancer patients suffered from recurrence and metastasis within 5 years with unfavorable prognosis.With the help of development and spread of cervical cancer screening technology,the early cervical carcinoma diagnosis rate has increased.However,we still lack effective predictors for predicting recurrence,metastasis and death.Therefore,a specific biomarker that can indicate poor prognosis of cervical cancer are needed.High-throughput sequencing has been used to detect the microbiome in many tumors..Different types of tumors have unique tumor microbiomes,and the microorganisms in the tumor microenvironment contribute to the occurrence and development of tumors.In colorectal cancer,there was evidence that high levels of Fusobacterium nucleatum were associated with worse outcome.Similarly,studies related to cervical cancer microbiome are mostly focused on cervicovaginal microbiome while the tumor microbes in cervical cancer remains obscure.Studies had confirmed that the abundance of Fusobacterium nucleatum in vaginal microenvironment with cervical cancer was much higher than that of normal tissue and precancerous.But its value in malignant reproductive system tumors remains to be further explored.Our study try to analyze the level of Fusobacterium nucleatum in cervical cancer tumors and the relationship with recurrence of cervical cancer,and finally try to find microbiological indicators that can evaluate and predict the prognosis of cervical cancer to provide new targets for further providing new treatment options.Objective The purpose of our study is to detect the levels of Fusobacterium nucleatum in cervical cancer tissues,and to analyze the relationship among Fusobacterium nucleatum,clinicopathological characteristics and prognosis.Additionally,we tried to assess the tumor growth capacity and gene expression related to tumor stemness and metastasis in cancer cell with diverse Fusobacterium nucleatum infiltration levels.Finally,we aimed to explore the clinical value of Fusobacterium nucleatum in predicting the prognosis of patients with cervical cancer.Material and methods This study included 112 patients who underwent surgical treatment for cervical squamous cell carcinoma at Guangdong Provincial People’s Hospital and Sun Yat-sen University Cancer Center from 2010 to 2015.The total DNA of 112 cervical malignant tumor tissues with frozen tissues,paraffin sections paired primary tumor,recurrent tumor tissues(stump recurrence or recurrence confined to the pelvis)and adjacent tumor tissues from 23 patients,as well as 20 patients with advanced stage III-IV were extracted.Further,the amount of Fusobacterium nucleatum DNA in the tissues were detected by use of a q PCR assay and RT-q PCR were used to detect the expression of cancer stem cell and metastasis-associated genes.At the same time,primary culture of cervical cancer cells with different Fusobacterium nucleatum level and differentiation degree were used for cell model and sphere formation assay was used to survey their self-renewal capacity.Statistical analysis was performed by IBM SPSS Soft 21(IBM Corporation;United States)and Graph Pad Prism 6(Graph Pad Software;United States).Continuous variables were compared by a t-test or chi-square test to examine relationship between Fusobacterium nucleatum levels expression and clinicopathological characteristics differences.Survival estimates were calculated using the Kaplan-Meier analysis and COX regression analysis.Results 1.Kaplan-Meier analyses indicated that the increased burden of intratumoral Fusobacterium nucleatum predicts worse PFS(P=0.001)and OS(P=0.012)in 112 locally advanced stage cervical cancer.2.The amount of Fusobacterium nucleatum in tumors was significantly higher than adjacent non-tumor tissues(P=0.0024).We observed a marked enrichment in recurrent lesion than primary cervical cancer tissues(P=0.0129).Furthermore,an obvious enrichment of this bacterium was revealed in advanced stage tissues(FIGO Ⅲ/Ⅳstage,P=0.0003).3.High intratumoral burdens of Fusobacterium nucleatum can be viewed as a survival independent risk factor for recurrence by univariate and multivariate analysis in the Cox proportional hazards regression model.4.The levels of local Fusobacterium nucleatum were correlated with tumor differentiation such that women with higher pathological grading tended toward having higher measures of abundances(poor vs.well/moderate differentiation;P = 0.0267).5.Sphere-formation were significantly increased when Fusobacterium nucleatum levels stood high in cervical cancer cell with increased expression of genes related to tumor stemness and invasion,which indicates that these cells possess the characteristics of cancer stem cells(CSCs)with a tendency to metastasize.Conclusions: 1.High levels of Fusobacterium nucleatum in cervical cancer tumors are related to the poor prognosis of cervical cancer;2.The abundance of Fusobacterium nucleatum in advanced stage and relapsed cervical cancer tissue is higher than that in primary cervical cancer tissue.3.With high intratumoral Fusobacterium nucleatum burdens,cervical cancer cells possess the characteristics of cancer stem cells(CSCs).