CCL2 and colorectal cancer: Moreover, Streptococcus bovis stimulates colorectal cancer cells to secrete cytokines such as IL-6, Scyb1, Ptgs2, IL-1β, TNF, and CCL2, thereby recruiting CD11b+ TLR-4+ immune cells to the tumor site, establishing an immunosuppressive microenvironment that fosters colorectal cancer progression78 . Peptostreptococcus anaerobius promotes colorectal cancer progression and resistance to anti-PD-1 therapy by activating integrin α2β1-NF-κB signaling to recruit CXCR2+ myeloid-derived suppressor cells (MDSCs) and directly enhancing MDSC immunosuppressive activity via lytC_22-Slamf4 interactions28.