JCES01.11 Altered Expression of Programmed Death-Ligand 1 after Neo-Adjuvant Chemotherapy in Patients with Lung Squamous Cell Carcinoma

Abstract

Programmed death-ligand 1 (PD-L1) is known to be over-expressed in non-small cell lung cancer (NSCLC). However, the impact of chemotherapy on the altered status of PD-L1 expression has not been examined for NSCLC. The present study was intended to examine the impact of neoadjuvant chemotherapy on PD-L1 expression and its prognostic significance in lung squamous cell carcinoma (SCC). Matched tumor samples were obtained from SCC patients prior to and after neoadjuvant chemotherapy. The expression of PD-L1 was evaluated by immunohistochemistry. Survival analysis was performed by the Kaplan-Meier method. A total of 76 eligible SCC patients were recruited. There were 51 males and 25 females with a median age of 60 (39-72) years. The smoking status was former (n=46) and never (n=34). Prior to neoadjuvant chemotherapy, PD-L1 expression was identified in 52.6% (40/76) of SCC patients while 61.8% (47/76) were positive for PD-L1 expression after neoadjuvant chemotherapy . Nine patients switched from negative to positive while another two patients’ samples showed the reverse of the above result. Multivariate analysis demonstrated that postoperative expression of PD-L1 was an independent prognostic factor for overall survival (HR=0.50, P=0.003), but not for PD-L1 expression prior to neoadjuvant chemotherapy. Neoadjuvant chemotherapy may up-regulate the expression of PD-L1. As compared with the status of PD-L1 expression prior to chemotherapy, the postoperative expression of PD-L1 is a better prognostic factor for overall survival in SCC.