Intratumoral microbiota: a new perspective in cancer initiation, development, and therapy

Microbes have been identified as significantly impacting human health. Considerable attention has been focused on how microbiota affects cancer initiation, development, and therapeutic response. Currently, the biological functions of intratumoral microbiota have been preliminarily elucidated in tumors with high microbial abundance. However, the biological roles of the microbiota and their clinical significance in tumors with low microbial abundance, to our knowledge, remain largely unexplored. This gap in understanding is primarily due to the limited sensitivity of current detection technologies. This review provides a detailed examination of intratumoral microbiota characteristics and their interactions with the tumor microenvironment, focusing on the microbiota composition in various systems and its clinical role in different tumor types. Furthermore, the review explores the potential applications of intratumoral microbiota in cancer immunotherapy, including their role as immune enhancers, new drug delivery targets, and anticancer therapeutic agents. In conclusion, these insights may facilitate the use of microbiota for cancer diagnosis, prognosis, and the development of new therapeutic strategies.