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PD-L1 expression is the routine clinical biomarker for the selection of patients to receive immunotherapy in non-small cell lung cancer (NSCLC). However, the application and best timing of immunotherapy in the resectable setting is still under investigation. We aimed to study the effect of chemotherapy on PD-L1 expression and tumor infiltrating lymphocytes (TILs), which is to date still poorly understood. Our retrospective, single-centre neoadjuvant cohort comprised 96 consecutive patients with NSCLC resected 2000-2016 after neoadjuvant therapy, including paired diagnostic chemo-naïve specimens in 53 cases. A biologically matched surgical cohort of 114 primary resected cases was included. PD-L1 expression, CD8 + TILs density and tertiary lymphoid structures were assessed on whole slides and correlated with clinico-pathological characteristics and survival. Seven/53 and 12/53 cases had lower respectively higher PD-L1 expressions after neoadjuvant therapy. Most cases (n = 34) showed no changes in PD-L1 expression, the majority of these harboring PD-L1 < 1% in both samples (21/34 [61.8%]). Although CD8 + TILs density was significantly higher after chemotherapy (p = 0.031) in resections compared to diagnostic biopsies, this might be due to sampling and statistical bias. No difference in PD-L1 expression or CD8 + TILs density was detected when comparing the neoadjuvant and surgical cohort. In univariable analyses, higher CD8 + TILs density, higher numbers of tertiary lymphoid structures but not PD-L1 expression were significantly associated with longer survival. Increased PD-L1 expression after neoadjuvant chemotherapy was not significantly associated with shorter 5-year survival, but the number of cases was very low. In multivariable analysis, only pT category and age remained independent prognostic factors. In summary, PD-L1 expression was mostly unchanged after neoadjuvant chemotherapy compared to diagnostic biopsies. The sample size of cases with changed PD-L1 expression was too small to draw conclusions on any prognostic value.

With the approval of pembrolizumab for first- and second-line treatment of PD-L1+ non-small cell lung cancer (NSCLC), PD-L1 testing by immunohistochemistry (IHC) has become a necessity. However, the DAKO autostainer ASL48 for the FDA approved DAKO 22C3 pharmDx assay is not broadly available in Switzerland and other parts of Europe. The primary goal of this study was to cross-validate the 22C3 anti-PD-L1 antibody on Benchmark Ultra (VBMU) and Leica Bond (LBO) immunostainers. IHC protocols were developed for 22C3 on both platforms with the 22C3phDx using ASL48 as reference. A tissue microarray (TMA) was constructed from 23 NSCLC specimens with a range of PD-L1 staining results. Empty TMA sections and the 22C3 antibody were distributed to 16 participants for staining on VBMU (8 centers) and/or LBO (12 centers) using the centrally developed protocols. Additionally the performance of the Ventana SP263 assay was tested in five centers. IHC scoring was performed centrally. Categorical PD-L1 staining (0-49% vs. 50-100%) did not significantly differ between centers using VBMU, whereas data from LBO were highly variable (p

Aims: A great deal of research is being conducted into PD-L1 immunohistochemistry (IHC) and tumour-infiltrating lymphocytes (TILs) as predictive or prognostic biomarkers for immunotherapy, although several practical issues exist concerning their assessment. The aim of this research was therefore to assess the importance of choice of materials and methods in PD-L1 and TILs scoring in oropharyngeal squamous cell carcinoma (OSCC). Methods and results: IHC for PD-L1 (SP142 and 22C3 clone) and TILs subtyping was performed on formalin-fixed paraffin-embedded tissue slides (biopsy, resection and/or lymph nodes specimens) of 99 patients with OSCC. A comparative analysis of PD-L1 and TILs scoring was made between different types of tissue specimens, between different PD-L1 clones, between TILs and different subsets of TILs and between the quantitative and semiquantitative assessments. PD-L1 scoring resulted in fair to moderate agreement for 22C3 and SP142 between various tissue specimens, with higher agreement at higher cut-off values, and in moderate agreement for 22C3 versus SP142. Evaluation by four independent observers proved substantial inter-rater agreement for both clones with high consistency in their ratings. Moderate agreement was observed for TILs and TILs subsets for the comparison between biopsy and resection. Lastly, strong correlations were found between quantitative and semiquantitative assessment for all PD-L1 and TILs scores. Conclusions: Our results highlight the challenges associated with the evaluation of PD-L1 and TILs in OSCC. Further research is warranted to evaluate the use of these biomarkers in order to allow implementation of PD-L1 and TILs infiltrate as biomarkers in daily clinical practice.

The association between programmed death ligand 1 (PD-L1) expression and survival among melanoma patients treated with chemotherapy is unclear.1-5 We retrospectively characterized PD-L1 levels in patients with melanoma treated at Aarhus University Hospital in Denmark (2001-2012) using a prototype immunohistochemistry assay (QualTek Molecular Laboratories, Goleta, California, USA) and investigated the association between PD-L1 and overall survival (OS) in patients who received chemotherapy or immunotherapy (interleukin-2, interferon, ipilimumab). None of the patients received pembrolizumab or nivolumab. This article is protected by copyright. All rights reserved.