Fusobacterium nucleatum (Fn) is frequently found in colorectal cancers (CRCs). High loads of Fn DNA are detected in CRC tissues with microsatellite instability-high (MSI-H), or with the CpG island hypermethylation phenotype (CIMP). Fn infection is also associated with the inflammatory tumor microenvironment of CRC. A subtype of CRC exhibits inflammation-associated microsatellite alterations (IAMA), which are characterized by microsatellite instability-low (MSI-L) and/or an elevated level of microsatellite alterations at selected tetra-nucleotide repeats (EMAST). Here we describe two independent CRC cohorts in which heavy or moderate loads of Fn DNA are associated with MSI-H and L/E CRC respectively. We also show evidence that Fn produces factors that induce γ-H2AX, a hallmark of DNA double strand breaks (DSBs), in the infected cells.

中文翻译：

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核梭形杆菌感染与大肠癌中两种类型的微卫星改变相关，并引发DNA损伤

在大肠癌（CRC）中经常发现核梭状芽胞杆菌（Fn）。在高微卫星不稳定性（MSI-H）或CpG岛超甲基化表型（CIMP）的CRC组织中检测到高负荷的Fn DNA。Fn感染也与CRC的炎性肿瘤微环境有关。CRC的一种亚型表现出与炎症相关的微卫星改变（IAMA），其特征是微卫星不稳定性低（MSI-L）和/或选定四核苷酸重复序列（EMAST）上微卫星改变的水平升高。在这里，我们描述了两个独立的CRC队列，其中Fn DNA的重负荷或中度负荷分别与MSI-H和L / E CRC相关。我们还显示证据表明Fn会在感染的细胞中产生诱导γ-H2AX（DNA双链断裂（DSBs）的标志）的因子。