IL1B and cancer: Furthermore, peritoneal macrophages engage in a synergistic crosstalk with cancer-associated fibroblasts (CAFs): CAFs secrete CXCL12 and TGF-β to reinforce macrophage M2 polarization, while macrophages reciprocally enhance CAF-mediated ECM remodeling through IL-1β secretion, collectively fostering a pro-metastatic stromal niche (57, 74, 75).