Programmed Cell Death-ligand 1 as Biomarker of Poor Prognosis in Patients with Gastrointestinal Stromal Tumour.

Background and aims: To explore the prognostic role of programmed cell death-ligand 1 (PD-L1) in patients with gastrointestinal stromal tumours (GISTs).

Methods: PD-L1 expression was detected using immunohistochemistry in tissue microarrays from 96 GISTs samples. Survival of patients was assessed using Kaplan - Meier analysis. Possible risk factors for GISTs were explored using Cox proportional hazards regression models. The role of PD-L1 in GISTs proliferation, invasion, and metastasis was assessed using colony formation assay, scratch, transwell invasion, and migration assays.

Results: Survival in GISTs patients was significantly associated with PD-L1 expression (p < 0.05). High PD-L1 expression in GISTs resulted in relatively short overall survival (p=0.016). Univariate regression analysis showed that PD-L1 was a risk factor for poor prognosis (p<0.05). Compared with the control group, knockdown of PD-L1 significantly decreased the colony formation rate, and cell migration and invasion were inhibited compared with the control group. The wound healing ability of PD-L1 knockdown group was significantly weaker than that of the control group.

Conclusions: The results suggest that overexpression of PD-L1 is a risk factor for a poor prognosis in patients with GISTs. Knockdown of PD-L1 significantly inhibited the development of GISTs. PD-L1 may serve as a biomarker for the poor prognosis of GISTs and a potential therapeutic target.