Comparative analysis of programmed death ligand 1 expression in paired cytologic and histologic specimens of non-small cell lung cancer.

The results demonstrate that in the absence of available histologic specimens, PD-L1 positivity in cytologic samples could be a reliable data for the oncologist to consider immune checkpoint inhibitor therapy. However, a comparison of cytologic and histologic samples has shown an underestimation of PD-L1 values in cytologic samples.