Viral and bacterial infections are involved in the development of human cancers, such as liver, nasopharyngeal, cervical, head and neck, and gastric cancers. Aberrant DNA methylation is frequently present in these cancers, and some of the aberrantly methylated genes are causally involved in cancer development and progression. Notably, aberrant DNA methylation can be present even in non-cancerous or precancerous tissues, and its levels correlate with the risk of cancer development, producing a so-called 'epigenetic field for cancerization'. Mechanistically, most viral or bacterial infections induce DNA methylation indirectly via chronic inflammation, but recent studies have indicated that some viruses have direct effects on the epigenetic machinery of host cells. From a translational viewpoint, a recent multicenter prospective cohort study demonstrated that assessment of the extent of alterations in DNA methylation in non-cancerous tissues can be used to predict cancer risk. Furthermore, suppression of aberrant DNA methylation was shown to be a useful strategy for cancer prevention in an animal model. Here, we review the involvement of aberrant DNA methylation in various types of infection-associated cancers, along with individual induction mechanisms, and we discuss the application of these findings for cancer prevention, diagnosis, and therapy.

中文翻译：

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感染对致癌作用的表观遗传影响：机制和应用。


病毒和细菌感染与人类癌症的发展有关，例如肝癌、鼻咽癌、宫颈癌、头颈癌和胃癌。异常的 DNA 甲基化经常存在于这些癌症中，并且一些异常甲基化的基因与癌症的发生和进展有关。值得注意的是，异常的DNA甲基化甚至可以存在于非癌性或癌前组织中，其水平与癌症发展的风险相关，产生所谓的“癌化的表观遗传场”。从机制上讲，大多数病毒或细菌感染通过慢性炎症间接诱导 DNA 甲基化，但最近的研究表明，一些病毒对宿主细胞的表观遗传机制有直接影响。从转化的角度来看，最近的一项多中心前瞻性队列研究表明，评估非癌组织中 DNA 甲基化的改变程度可用于预测癌症风险。此外，抑制异常 DNA 甲基化被证明是动物模型中预防癌症的有效策略。在这里，我们回顾了异常 DNA 甲基化在各种类型的感染相关癌症中的参与情况以及个体诱导机制，并讨论了这些发现在癌症预防、诊断和治疗中的应用。