Jun Chen, Hui Li, Ronglin Pang, Jia Huang

Programmed death-ligand 1 (PD-L1) is found to be overexpressed in non-small cell lung cancer. The present study intended to evaluate the status of PD-L1 expression in patients with resection and recurrent lung adenocarcinoma. Matched resection and recurrent tumor samples were harvested from 65 lung adenocarcinoma patients. Immunohistochemistry was used to evaluate the status of PD-L1 expression. Kaplan-Meier method was used for survival analysis. A total of 65 patients of lung adenocarcinoma were enrolled. They underwent complete resection and had recurrence after adjuvant treatment. PD-L1 expression was identified in 43.1% (28/65) of resection samples vs 55.4% (36/65) of recurrent samples. Ten patients shifted from negative to positive, whereas another two samples showed the opposite. Patients with PD-L1 expression showed worse disease-free survival than the PD-L1-negative counterparts. The expression of PD-L1 in recurrent samples was a significant favorable factor for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) (11.2 vs 8.2 months, P=0.030). The status of PD-L1 expression may alter between resection and recurrent samples. Also, the status of PD-L1 expression after recurrence is a better prognostic factor for EGFR-TKIs.