Activated monocytes in peritumoral stroma of hepatocellular carcinoma foster immune privilege and disease progression through PD-L1

Macrophages (Mphi) are prominent components of solid tumors and exhibit distinct phenotypes in different microenvironments. We have recently found that tumors can alter the normal developmental process of Mphi to trigger transient activation of monocytes in peritumoral stroma. We showed that a fraction of monocytes/Mphi in peritumoral stroma, but not in cancer nests, expresses surface PD-L1 (also termed B7-H1) molecules in tumors from patients with hepatocellular carcinoma (HCC). Monocytes activated by tumors strongly express PD-L1 proteins with kinetics similar to their activation status, and significant correlations were found between the levels of PD-L1(+) and HLA-DR(high) on tumor-infiltrating monocytes.…

• NN
  National Natural Science Foundation of China

  Awards: 2008ZX10002-019, 30730086