EPCAM and non-small cell lung carcinoma: Using CD133 and EpCAM to mark CSCs, Raniszewska et al. established the presence of PD-L1 on presumed CSCs from lymph node metastases in endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) samples from patients with non-small-cell lung cancer (NSCLC) by flow cytometry [25].