Prognostic significance of PD-L1 expression and 18 F-FDG PET/CT in surgical pulmonary squamous cell carcinoma

// Minghui Zhang 1, * , Dalong Wang 2, 3, * , Qi Sun 4, * , Haihong Pu 1 , Yan Wang 5 , Shu Zhao 1 , Yan Wang 1 and Qiangyuan Zhang 1 1 Department of Medical Oncology, Harbin Medical University Cancer Hospital, Harbin 150081, China 2 Department of Radiology, The Second Affiliated Hospital of Harbin Medical University, Harbin 150040, China 3 Department of PET/CT, Harbin Medical University Cancer Hospital, Harbin 150081, China 4 Department of Radiology, Harbin Medical University Cancer Hospital, Harbin 150081, China 5 Department of Medical Oncology, Heilongjiang Provincial Hospital, Harbin 150000, China * These authors have contributed equally to this work Correspondence to: Qiangyuan Zhang, email: zhma1965210@163.com Keywords: programmed cell death ligand 1, squamous cell carcinoma, prognostic factor, PET-CT Received: March 14, 2017      Accepted: April 28, 2017      Published: May 29, 2017 ABSTRACT Programmed cell death-ligand 1 (PD-L1) expression is commonly observed in non-small cell lung cancer (NSCLC). The prognostic value of PD-L1 expression and the maximum standardized uptake value (SUVmax) on 18F-Fluorodeoxyglucose positron emission tomography ( 18 FDG-PET) in surgical pulmonary squamous cell carcinoma(SCC)remains unclear. Furthermore, the correlation between the SUVmax and PD-L1 expression has not been assessed. Thus, the purpose of this study was to investigate the correlation between PD-L1 expression and the SUVmax on 18 FDG-PET and to examine the prognostic significance of PD-L1 expression and the SUVmax in surgical pulmonary SCC. Expression of PD-L1 was examined in 84 patients with resected SCC using immunohistochemistry. Positive PD-L1 expression in tumour cells was observed in 58.3% (49/84) of patients with SCC. High PD-L1 expression levels were significantly correlated with histological differentiation (P=0.006), and a high SUVmax was associated with histological differentiation (P=0.037), and lymph node metastasis (P=0.025).Spearman’s test showed that there was a significant correlation between PD-L1 expression levels and the SUVmax. High PD-L1 expression levels and a high SUVmax were both independent risks factors for poor overall survival. Our results suggested that high PD-L1 expression levels and a high SUVmax was associated with poor prognosis in surgical pulmonary SCC. The existence of a statistically significant correlation between the SUVmax and PD-L1 expression levels justifies exploring the usefulness of the SUVmax as a predictor of PD-1/PD-L1 inhibitor activity.