CLCF1 and cancer: This activation supports the survival and function of TANs while simultaneously inhibiting the immune response of T cells via the PD-1/PD-L1 pathway.498 Furthermore, the upregulation of CXCL6 and TGF-β in cancer cells is triggered by cardiotrophin-like cytokine factor 1 (CLCF1) from CAFs, thereby promoting N2 neutrophil polarization.499 MDSCs are a cellular population originating from the bone marrow, consisting of immature marrow cells and progenitors.