The tumor–microbe connection

The discovery of tumor-associated bacteria (TAB) challenges the traditional view of tumors as sterile environments. These microbes are engaged in a complex dialog with the other components of the tumor microenvironment (TME), influencing immunity, metastasis, and treatment response. Yet the precise mechanisms by which TAB influence tumor biology remains incompletely understood. Deciphering the complex host-microbe interactions could unlock novel therapeutic strategies to reshape the TME and improve treatment outcomes. Here we summarize the key findings in the field, highlighting the most outstanding questions regarding bacterial sources, the roles of TAB in cancer, and their interactions with the other cellular components of the TME.