Intratumoral microbiome in head and neck paragangliomas

Head and neck paragangliomas (HNPGLs) are rare neoplasms arising from paraganglia of the parasympathetic nervous system. HNPGLs are characterized by high vascularity and are located in proximity to major vessels and nerves, which may be potential sources of microbial invasion in these tumors. There have been no studies in the literature on the microbiota in HNPGLs. Investigation of the microbiome associated with paragangliomas is important for understanding tumor pathogenesis. In this study, we investigated the microbiome composition in two sets of HNPGLs. First, 29 fresh-frozen tissues were subjected to 16S RNA gene sequencing; concurrently, a panel of candidate laboratory-derived contaminants was investigated. Second, we analyzed microbial reads from whole transcriptome sequencing data obtained for 82 formalin-fixed paraffin-embedded (FFPE) HNPGLs. The bacterial diversity in FF tumors was found to be significantly lower than that observed in FFPE HNPGLs. Based on 16S amplicon sequencing, only seven bacterial families were identified as potential tumor inhabitants: Bryobacteraceae, Enterococcaceae, Neisseriaceae, Legionellaceae, Vibrionaceae, Obscuribacteraceae, and Mycobacteriaceae. However, RNA-Seq demonstrated higher sensitivity for identifying microbiome composition and revealed abundant bacterial families that partially correlated with those previously described in pheochromocytomas and extra-adrenal paragangliomas. No viruses were found in HNPGLs. In summary, our findings indicate the presence of a microbiome in HNPGLs, comprising a number of bacterial families that overlap with those observed in pheochromocytomas/paragangliomas and glioblastomas.

头颈部副神经节瘤（HNPGLs）是一类起源于副交感神经系统副神经节的罕见肿瘤。该类肿瘤具有高度血管化的特征，且多紧邻大血管与神经，这或为该类肿瘤发生微生物侵袭的潜在条件。目前尚无文献对头颈部副神经节瘤中的微生物组开展相关研究。探究与副神经节瘤相关的微生物组，对于阐明肿瘤发病机制具有重要意义。本研究针对两类头颈部副神经节瘤样本的微生物组构成展开了探究：其一，对29例新鲜冰冻组织样本进行16S核糖体RNA基因测序，同时对一系列实验室来源的潜在污染物进行排查分析；其二，对82例福尔马林固定石蜡包埋（FFPE）头颈部副神经节瘤的全转录组测序数据中的微生物读段进行分析。研究发现，新鲜冰冻组织样本中的细菌多样性显著低于福尔马林固定石蜡包埋样本。基于16S扩增子测序结果，仅鉴定出7个可作为潜在肿瘤定植菌的细菌科：Bryobacteraceae、Enterococcaceae、Neisseriaceae、Legionellaceae、Vibrionaceae、Obscuribacteraceae以及Mycobacteriaceae。但RNA测序（RNA-Seq）在微生物组构成鉴定方面展现出更高的灵敏度，其鉴定出的丰富细菌科类群有部分与此前在嗜铬细胞瘤及肾上腺外副神经节瘤中报道的类群存在关联。未在头颈部副神经节瘤样本中检测到病毒。综上，本研究结果证实头颈部副神经节瘤中存在微生物组，其所含的细菌科类群与嗜铬细胞瘤/副神经节瘤及胶质母细胞瘤中发现的类群存在部分重叠。