Enterococcus and cancer: from mechanistic insights to clinical translation.

Despite advances in traditional therapies, the global burden of malignant tumors remains substantial. Although immunotherapy has achieved remarkable breakthroughs by activating the host immune system, its clinical benefits are limited to a subset of patientsowing to low response rates and drug resistance. Emerging evidence highlights the pivotal role of the gut microbiota in determining immunotherapy outcomes. Within this ecosystem, the genus Enterococcus acts as a "double-edged sword": whereas certain strains can enhance antitumor immunity, other species notably Enterococcus faecalis, drive tumor progression by inducing DNA damage and inflammatory cascades. Therefore, elucidating the intricate interactions between Enterococcus and the host immune system is imperative for optimizing immunotherapeutic strategies and developing novel microbiome-based therapies.