Article Abstract

Upregulation of programmed death ligand 1 and epidermal growth factor receptor is associated with poor prognosis in gastric cancer

Authors: Wei Wei, Dachuan Zhang, Bin Xu, Jingting Jiang, Changping Wu


Background: Programmed death ligand-1 (PD-L1) and epidermal growth factor receptor (EGFR) are both expressed on the surface of gastric cancer cells. We aimed to evaluate the relationships between protein expression levels and patient clinicopathologic characteristics as well as their prognostic impacts.
Methods: The expression levels of PD-L1 and EGFR on tumor tissues and adjacent normal tissues were measured by immunohistochemistry in 90 cases of human gastric adenocarcinoma. The relationships of protein expression with clinicopathologic characteristics and prognosis were calculated by SPSS version 21.
Results: PD-L1 and EGFR protein expression were upregulated in tumor tissues compared with adjacent normal tissues (P=0.036, P<0.001, respectively). PD-L1 expression was related with tumor locations and overall survival. EGFR expression was related with patient age. Kaplan-Meier analysis demonstrated that patients with elevated expression of PD-L1 and EGFR presented significantly shorter overall survival (P=0.044, P=0.006, respectively). Univariate analysis revealed that PD-L1 positive expression, EGFR overexpression, low differentiation, depth of invasion (T stage), lymph node invasion (N stage) and distant metastasis (M stage) and vascular invasion were associated with worse overall survival. Multivariate analysis identified PD-L1 overexpression, differentiation, lymph node invasion, distant metastasis and vascular invasion to be potential independent prognostic factors. No correlation was found between PD-L1 and EGFR expression, yet patients with co-expression of both PD-L1 and EGFR tended to show a worse prognosis than the rest.
Conclusions: Our findings suggest that elevated expressions of PD-L1 and EGFR are prognostic factors for shorter overall survival respectively. Patients with co-expression of both tended to have worse prognosis.