PLoS ONE (Jan 2020)

PD-L1 expression in gastroenteropancreatic neuroendocrine neoplasms grade 3.

  • Abir Salwa Ali,
  • Seppo W Langer,
  • Birgitte Federspiel,
  • Geir Olav Hjortland,
  • Henning Grønbæk,
  • Morten Ladekarl,
  • Staffan Welin,
  • Lene Weber Vestermark,
  • Johanna Arola,
  • Pia Osterlund,
  • Ulrich Knigge,
  • Halfdan Sørbye,
  • Patrick Micke,
  • Lars Grimelius,
  • Malin Grönberg,
  • Eva Tiensuu Janson

DOI
https://doi.org/10.1371/journal.pone.0243900
Journal volume & issue
Vol. 15, no. 12
p. e0243900

Abstract

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Gastroenteropancreatic neuroendocrine neoplasms grade 3 (GEP-NENs G3) are rare tumors. These highly aggressive neoplasms are traditionally treated with platinum-based chemotherapy in combination with etoposide. Immune checkpoint proteins such as programmed cell death ligand (PD-L1) may have a role in different cancers allowing them escape the immune system and hence, progress. We aimed to investigate the immunohistochemical expression of PD-L1 in GEP-NEN G3 and evaluate its correlation to clinical parameters. In a cohort of 136 patients, 14 (10%) expressed PD-L1 immunoreactivity; four (3%) patients in the tumor cells and 10 (7%) had immunoreactive immune cells. PD-L1 expression did not correlate to clinical parameters, progression-free survival or overall survival. We conclude that PD-L1 expression is present only in a subset of GEP-NEN G3 patients. Further studies are needed to fully understand the role of PD-L1 in patients with GEP-NEN G3, including the future possibility for treatment with immune checkpoint inhibitors.