J Cancer 2016; 7(5):484-489. doi:10.7150/jca.13711
The Impact of PD-L1 Expression in Patients with Metastatic GEP-NETs
1. Division of Hematology-Oncology, Department of Medicine,
2. Department of Pathology & Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
*S.T.K and S.Y.H. contributed equally to this work.
Kim ST, Ha SY, Lee S, Ahn S, Lee J, Park SH, Park JO, Lim HY, Kang WK, Kim KM, Park YS. The Impact of PD-L1 Expression in Patients with Metastatic GEP-NETs. J Cancer 2016; 7(5):484-489. doi:10.7150/jca.13711. Available from http://www.jcancer.org/v07p0484.htm
Programmed death-ligand 1 (PD-L1), which is expressed on many cancer cells, interacts with PD1 expressed on the surface of T cells, inhibiting the T cells and blocking the antitumor immune response. Expression of PD-L1 in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has not been studied. We investigated the impact of PD-L1 expression in 32 patients with metastatic GEP-NET.
The expression of PD-L1 was evaluated using an anti-PD-L1 immunohistochemistry (IHC) antibody optimized for staining of formalin-fixed paraffin-embedded (FFPE) tissue samples. The correlation between PD-L1 and clinicopathological data including survival and response to systemic treatments was analyzed.
Primary sites were 24 foregut-derived GEP-NETs, including stomach (n=1), duodenum (n=2), biliary tract (n=7), and pancreas (n=14), and 8 hindgut-derived GEP-NETs of the distal colon and rectum. Among the 32 patients with metastatic GEP-NET analyzed in this study, 7 (21.9%) had expression of PD-L1 in tumor tissues. Expression of PD-L1 was significantly associated with high-grade WHO classification (grade 3) (p=0.008) but not with gender, primary site, and number of metastatic sites (p>0.05). The status of PD-L1 expression was statistically associated with progression-free survival (PFS) for first-line systemic treatment (p=0.047). Moreover, the status of PD-L1 expression could significantly predict overall survival (p=0.037).
The expression of PD-L1 was associated with higher WHO tumor grade (grade 3) in metastatic GEP-NETs. PD-L1 expression had both predictive and prognostic value for survival of patients with metastatic GEP-NETs.
Keywords: Programmed death-ligand 1 (PD-L1), Gastroenteropancreatic neuroendocrine tumor (GEP-NET), WHO classification.