Abstract
The cancer microbiome is an emerging concept that is referred to as the microorganism communities associated with cancer. There has been controversy in terms of the bona fide functions of the microbiome in carcinogenesis and cancer development, since the microorganisms were first observed within tumor tissues. Recently, there has been growing evidence showing that the microbiome indeed plays a role in cancer initiation, development, diagnosis, and treatment through diverse mechanisms and interactions between host cells and microbes. Rather than contaminants or artifacts, the cancer microbiome has been proven to be alive in the tumor microenvironment and possess significantly differential physiological and morphological properties compared to the corresponding environmental microorganisms. However, due to the low abundance of microbes within cancer tissues (especially the intratumoral microbiota) and lack of efficient analytical tools (e.g., sensitive antibodies, sensors, and probes), there are still a number of challenges and question marks in this fast-growing field. In this chapter, we made a systematic summary of the cancer microbiome, specifically focusing on its discovery and the recent research advances with respect to the studies on its functions and corresponding technology development.