Intratumoral Bacteria: Accomplices in Cancer Progression and Emerging Therapeutic Targets

ABSTRACT Once regarded as mere contaminants, intratumoral bacteria are now recognized as functional contributors to cancer progression, promoting therapeutic resistance and metastatic dissemination through diverse mechanisms. On the therapeutic front, innovative strategies are reshaping cancer treatment: synthetic microbial consortia (SMC) counteract Fusobacterium nucleatum ‐associated chemoresistance in colorectal cancer, magnetotactic bacteria (MSR‐CPT/APP@LPs) enhance anti‐PD‐1 efficacy by 40% through spatially targeted co‐delivery of chemotherapeutic and immunomodulatory agents, and the Tumor Microbiome Survival Index robustly predicts survival in pancreatic cancer (4‐year area under the curve = 0.781). We further propose an ecological management framework that combines longitudinal microbiome profiling with precision interventions, advocating for causal validation, such as through Mendelian randomization, and standardized clinical translation to fully exploit this emerging dimension of precision oncology.