PD-L1 expression in HNPCC-associated colorectal cancer

Pathol Res Pract. 2017 Dec;213(12):1552-1555. doi: 10.1016/j.prp.2017.09.012. Epub 2017 Sep 18.


Background: PD-L1 immunohistochemistry is predictive for molecular inhibitors of PD-1/PD-L1 immune checkpoint. Therefore, this study evaluated the PD-L1 expression in patients with Hereditary Non-Polyposis Colorectal Cancer (HNPCC).

Methods: Immunohistochemical expression of PD-L1 in carcinoma cells, stromal macrophages and lymphocytes of 40 HNPCC-patients with colorectal cancer was scored semi-quantitatively.

Results: Focal (2 cases) to extensive (2 cases) PD-L1-immunopositivity of carcinoma cells was detected in 4 out of 40 cases (10.0%). Stromal macrophages were immunopositive in 28 out of 40 cases (70.0%). Lymphocytes showed PD-L1 expression in 3 out of 40 cases (7.5%). Simultaneous immunopositivity of stromal macrophages and tumor cells was detected in two MLH1/PMS2-deficient and two MSH2/MSH6-deficient cases.

Conclusion: A subset of HNPCC-associated colorectal cancers in this study clearly showed PD-L1 expression of tumor epithelia and immune cells, therefore, the detection of PD-L1 status is useful.

Keywords: Colorectal cancer; HNPCC; Lynch syndrome; Mismatch repair enzymes; PD-L1.

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Adult
  • B7-H1 Antigen / metabolism*
  • Carrier Proteins / metabolism
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism*
  • Colorectal Neoplasms, Hereditary Nonpolyposis / diagnosis
  • Colorectal Neoplasms, Hereditary Nonpolyposis / metabolism*
  • DNA Mismatch Repair / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • MutL Protein Homolog 1 / metabolism
  • Mutation / genetics
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*


  • Adaptor Proteins, Signal Transducing
  • B7-H1 Antigen
  • CD274 protein, human
  • Carrier Proteins
  • Nuclear Proteins
  • MutL Protein Homolog 1