Clinicopathologic Correlation With Expression of PD-L1 on Both Tumor Cells and Tumor-infiltrating Immune Cells in Patients With Non-Small Cell Lung Cancer.

Our study was to evaluate the concordance of programmed cell death-ligand 1 (PD-L1) expression between 22C3 and SP263 assay and explore the association of clinicopathologic features with expression of PD-L1 on both tumor cells (TC) and tumor-infiltrating immune cells (IC). We retrospectively assessed the PD-L1 expression in 305 patients with lung adenocarcinoma or adenosquamous carcinoma by 22C3 and SP263 assay. The association of PD-L1 expression by 22C3 assay with clinicopathologic features was also analyzed. The prevalence of PD-L1 expression by 22C3 assay was 20.7% with a ≥50% cutoff and 46.6% with a ≥1% cutoff. The concordance rates between 2 PD-L1 assays while using 1%, 5%, 25%, and 50% positive TC as the cutoffs were 91.8%, 93.1%, 95.1% and 99.0%, respectively. For PD-L1 expression on IC, the concordance rate was 93.4% using a 1% cutoff. According to the results of 22C3 assay, high PD-L1 expression (using a ≥50% cutoff) on TC was significantly associated with smoking, advanced stage disease, and KRAS mutation. PD-L1 expression on IC was significantly associated with smoking and KRAS mutation. PD-L1 expression on TC and IC were both significantly associated with average number of cigarettes smoked ≥20 per day. The 22C3 and SP263 assays were highly concordant for assessment of PD-L1 expression on TC and IC. Patients with KRAS mutation and smoking history, particularly those having a large number of cigarettes smoked per day, were more likely to have PD-L1 expression on both TC and IC.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. https://creativecommons.org/licenses/by-nc-nd/4.0/.