The baseline oral microbiota predicts the response of locally advanced oral squamous cell carcinoma patients to induction chemotherapy: A prospective longitudinal study

Among oral squamous cell carcinoma (OSCC) patients who receive docetaxel, cisplatin, and 5-fluorouracil (TPF) induction chemotherapy, those with a favorable pathological response tend to obtain satisfactory clinical outcomes, while the total population exhibit no survival benefit. Thus, there is an urgent need to improve the therapeutic effect of TPF by applying personalized treatment according to distinct biomarkers.In the present study, we collected oral rinse samples from 44 OSCC patients enrolled in our prospective multicenter random phase II trial before TPF induction chemotherapy to conduct 16S rRNA gene sequencing and metagenomic analysis. Patients were administrated with two cycles of TPF induction chemotherapy (75 mg/m2 cisplatin and 75 mg/m2 docetaxel on day 1 and 750 mg/m2 fluorouracil from the first to the fifth day), and then divided into responsive and nonresponsive groups according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.In the 16S rRNA gene sequence analysis, Fusobacterium and Mycoplasma were more enriched in the nonresponsive group, while Slackia was more enriched in the responder group at the genus level. In the metagenomic shotgun sequencing analysis, Fusobacterium nucleatum was more enriched in the nonresponsive group. Functional analysis showed that the platinum drug resistance pathway and microRNAs in cancer and RNA degradation pathways were remarkably associated with patient sensitivity to induction chemotherapy.Our data suggest that the oral microbiome may play an important role in the OSCC patient sensitivity to TPF induction chemotherapy and offer novel potential biomarkers for predicting the response to TPF induction chemotherapy.