21:T48c,Colorectal cancer (CRC) is one of the most common malignant tumors and is associated with Fusobacterium nucleatum (F. nucleatum, Fn) infection. In this study, we explored the role of F. nucleatum in the CRC metastasis. Our results showed that the abundance of F. nucleatum was enriched in the feces and tumors of patients with CRC and tended to increase in stage IV compared to stage I in patients with metastatic CRC. Tumor-derived CCL20 activated by F. nucleatum not only increases CRC metastasis, but also participates in the reprograming of the tumor microenvironment. F. nucleatum promoted macrophage infiltration through CCL20 activation and simultaneously induced M2 macrophage polarization, enhancing the metastasis of CRC. In addition, we identified using database prediction and luciferase activity hat miR-1322, a candidate regulatory micro-RNA, could bind to CCL20 directly. F. nucleatum infection decreased the expression of miR-1322 by activating the NF-κB signaling pathway in CRC cells. In conclusion, F. nucleatum promotes CRC metastasis through the miR-1322/CCL20 axis and M2 polarization.22:T46f,Neutrophils play a major role in cancer biology and both pro- and antitumoral functions of tumor-infiltrating neutrophils have been described. We have shown that tumors, by releasing G-CSF into the bloodstream, prime circulating neutrophils to form neutrophil extracellular traps (NETs) and we have detected the presence of NETs within the tumor microenvironment. Here, we report, using PAD4-deficient mice with a defect in neutrophil chromatin decondensation and NET formation, that the priming of neutrophils toward NETosis favors tumor growth. Interestingly, in a tumor model that does not release G-CSF and in which neutrophils are not primed for NETosis, PAD4-deficiency did not reduce tumor growth. However, supplying exogenous G-CSF to the wild-type (WT) host promoted intratumoral NETosis and tumor growth. Taken together, our results suggest that the priming of neutrophils for NETosis by the tumor or its environment leads to the accumulation of intratumoral NETs and a growth advantage to the tumor. Our work unveiled a pro-tumoral role for NETs which strengthens their potential as a new target in the fight against cancer.

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