%0 Journal Article %T Real-world PD-L1 testing and distribution of PD-L1 tumor expression by immunohistochemistry assay type among patients with metastatic non-small cell lung cancer in the United States %A Frank Xiaoqing Liu %A Pallavi D. Patwardhan %A Thomas Burke %A Vamsidhar Velcheti %A Xin Chen %A Xiting Cao %J Archive of "PLoS ONE". %D 2018 %R 10.1371/journal.pone.0206370 %U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6224125/