From there, polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) rise via a TLR4-overexpressed pathway (associated with CCA progression and worse disease outcomes) and the CXCL1–CXCR2 axis, promoting chronic inflammation, tumor proliferation and reducing anti-tumor activity [77]. The gene discussed is CXCR2; the disease is cholangiocarcinoma.