Background PD-L1 expression is an important biomarker for patients to choose PD-1/PD-L1 inhibitors treatment. However, the correlation between PD-L1 expression and clinicopathological characteristics of non-small cell lung cancer (NSCLC) is still controversial.
Objective To explore the correlation between PD-L1 expression detected by Immunohistochemistry (22C3) and the clinicopathological characteristics in surgically resected NSCLC patients.
Methods The medical records of NSCLC patients who were diagnosed and underwent surgery in the First Medical Center of Chinese PLA General Hospital from March to August in 2019 were collected, and the correlation between the PD-L1 expression and clinicopathological characteristics was analyzed.
Results A total of 178 patients were enrolled in this study, with 82 males and 96 females, mean age of 58.7 years. PD-L1 expression rate of 1% or greater was defined as PD-L1-positive, and the positive PD-L1 expression rate was 51.7%. Compared with the lung adenocarcinoma, the PD-L1 expression was significantly higher in squamous cell carcinoma (77.8% vs 47.0%, P=0.003). In the patients with lung adenocarcinoma, multivariate analysis indicated that expression of PD-L1 was higher in patients with lymph node metastasis than those without lymph node metastasis (OR=3.392, 95% CI: 1.055 - 10.90, P=0.040), and patients with high Ki-67 index were tended to have higher PD-L1 expression (OR=1.028, 95% CI: 1.004 - 1.054, P=0.024). Moreover, Spearman rank correlation demonstrated that PD-L1 expression was positively correlated with Ki-67 index (r=0.363, P＜0.001).
Conclusion PD-L1 expression in lung squamous cell carcinoma is significantly higher than that in adenocarcinoma. Lymph node metastasis and Ki-67 index are the influencing factors of PD-L1 expression in lung adenocarcinoma. The results of our study may be helpful for screening patients with higher PD-L1 expression in NSCLC patients successfully.
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