PD‐L1 expression in NSCLC: Role of cell blocks and concordance between samples

Background PD‐L1 immunohistochemistry is currently performed in patients with advanced non‐small cell lung carcinoma (NSCLC) to identify responders to immune checkpoint inhibitors. Cell blocks from fine needle aspiration of NSCLC are frequently used for diagnostic purposes. The aims of the study are to analyze: (a) the distribution of PD‐L1 in cell blocks, in comparison to biopsies and surgical specimens; (b) the concordance of PD‐L1 in...