An overwhelming number of research articles have reported a strong relationship of the microbiome with cancer. Microbes have been observed more commonly in the body fluids like urine, stool, mucus of people with cancer compared to the healthy controls. The microbiota is responsible for both progression and suppression activities of various diseases. Thus, to maintain healthy human physiology, host and microbiota relationship should be in a balanced state. Any disturbance in this equilibrium, referred as microbiome dysbiosis becomes a prime cause for the human body to become more prone to immunodeficiency and cancer. It is well established that some of these microbes are the causative agents, whereas others may encourage the formation of tumours, but very little is known about how these microbial communications causing change at gene and epigenome level and trigger as well as encourage the tumour growth. Various studies have reported that microbes in the gut influence DNA methylation, DNA repair and DNA damage. The genes and pathways that are altered by gut microbes are also associated with cancer advancement, predominantly those implicated in cell growth and cell signalling pathways. This study exhaustively reviews the current research advancements in understanding of dysbiosis linked with colon, lung, ovarian, breast cancers and insights into the potential molecular targets of the microbiome promoting carcinogenesis, the epigenetic alterations of various potential targets by altered microbiota, as well as the role of various chemopreventive agents for timely prevention and customized treatment against various types of cancers.

大量研究文章报道了微生物组与癌症的密切关系。与健康对照者相比，在癌症患者的尿液、粪便、粘液等体液中更常发现微生物。微生物群负责各种疾病的进展和抑制活动。因此，为了维持健康的人体生理机能，宿主和微生物群的关系应该处于平衡状态。这种平衡的任何紊乱，称为微生物菌群失调，都会成为人体更容易患免疫缺陷和癌症的主要原因。众所周知，其中一些微生物是致病因子，而其他微生物可能会促进肿瘤的形成，但人们对这些微生物通讯如何导致基因和表观基因组水平的变化以及触发和促进肿瘤生长知之甚少。各种研究报告说，肠道中的微生物会影响 DNA 甲基化、DNA 修复和 DNA 损伤。被肠道微生物改变的基因和通路也与癌症进展有关，主要是那些与细胞生长和细胞信号通路有关的基因和通路。这项研究详尽地回顾了当前在理解与结肠癌、肺癌、卵巢癌、乳腺癌相关的生态失调方面的研究进展，以及对微生物组促进致癌作用的潜在分子靶点的洞察，改变微生物群对各种潜在靶点的表观遗传改变，