Abstract 1024: Tumor intrinsic properties associate with differential effects on CD8+ tumor-infiltrating lymphocyte density and immune gene expression in non-small cell lung cancer (NSCLC) samples

Abstract

Abstract Introduction: Anti-tumor immune response is controlled by a complex interaction between the immune system, tumor cells, and associated stroma. Expression of major histocompatibility complex class I (MHC I) and MHC class II (MHC II) antigens may be dysregulated in cancer, leading to alterations in the tumor antigen presentation profile. Stage I–III resected NSCLC tumor samples were profiled to study the relationship between MHC I, MHC II, and programmed death ligand 1 (PD-L1) tumor cell (TC) expression with tumor-associated inflammation. Here we report the potential impact of respective profiles on tumor immune response. Methods: 53 adenocarcinoma (NSCLC-AD) and 51 squamous cell carcinoma (NSCLC-SQ) stage I–III resected formalin-fixed, paraffin-embedded tumor specimens from commercial sources were stained by immunohistochemistry for MHC I (HLA-A,B,C), MHC II (HLA-DP,DQ,DR), and PD-L1 and TC expression was assessed by manual pathologist review. CD8+ cell density was quantified using Definiens image analysis algorithms for the intraepithelial tumor region. RNA extracted from the samples was analyzed by RNAseq, with data available for 48 NSCLC-AD and 46 NSCLC-SQ specimens. A 25-gene IFN-gamma gene signature (IFNG score) was used to study the association of T-cell inflammation with other biomarkers. Results: Of all NSCLC-AD and NSCLC-SQ specimens, 85% showed either complete (<20% TC) or partial (20–80% TC) loss of TC MHC I, while TC MHC II was increased (>1%; MHCIIhi) in 60% of NSCLC-AD and 18% of NSCLC-SQ. Quantitative analysis of CD8 in the tumor microenvironment (TME) revealed a significantly reduced intraepithelial density of CD8+ tumor-infiltrating lymphocytes (TILs) in NSCLC-AD (P=0.009) and NSCLC-SQ (P=0.01) with complete MHC I loss. In contrast, intraepithelial CD8+ TILs were significantly increased in MHCIIhi tumors for both NSCLC-AD (P=0.004) and NSCLC-SQ (P=0.006). Tumors displaying both MHCIIhi and retained MHC I demonstrated the highest TIL density. Gene expression associated with IFN-gamma response was increased in tumors with retained MHC I (P=0.0036) and MHCIIhi samples (P<0.001). In NSCLC-AD and NSCLC-SQ, 38% and 59% had PD-L1 expression ≥1%, respectively. PD-L1 expression correlated with CD8 density and IFNG score in NSCLC-AD, but not in NSCLC-SQ. Conclusions: Understanding the role of the antigen presentation machinery in immune activation and evasion in the TME is important to predict responses to immunotherapy. These data suggest that the expression of MHC I, MHC II, and PD-L1 by tumor cells may play a role in guiding the localization of CD8+ T cells in the TME with differential effects dependent on histologic subtype. The lack of correlation between inflammation and PD-L1 expression in stage I–III NSCLC-SQ suggests an alternate PD-L1 induction mechanism in a subset of those tumors. Citation Format: Cyrus Hedvat, Keyur Desai, Dimple Pandya, Peter Szabo, Johannes Zimmermann, Jan Lesniak, Scott Ely, Sujaya Srinivasan, Xi-Tao Wang, Michele French, Robin Edwards. Tumor intrinsic properties associate with differential effects on CD8+ tumor-infiltrating lymphocyte density and immune gene expression in non-small cell lung cancer (NSCLC) samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1024.