Abstract 2841: Differential immune responses to HPV-positive and HPV-negative head and neck cancer

Abstract

Abstract Background: Immune checkpoint inhibitors (ICIs) have been effective in treating several solid tumor malignancies, including head and neck squamous cell carcinoma (HNSCC); however, less than 20% of patients benefit from even the most promising ICI drugs. There is a lack of accurate predictors for response to ICI treatment in HNSCC and little is known about which types of immune cells have a more dominant impact on T-cell infiltration in HPV-positive and HPV-negative HNSCC. The main objective of our study was to identify the unique immune signatures of HPV-positive and HPV-negative HNSCC and to determine the major immune suppressive entities within their respective tumor microenvironments. Methods: We retrospectively analyzed a cohort of 102 HNSCC patients (44 HPV-positive, 58 HPV-negative), a subset of whom went on to receive ICI therapy later in their treatment course. We determined an immune signature by HPV-status using multiplex gene expression analysis (NanoString Immune Profiler). We also used multiplex immunohistochemistry (MIHC) to simultaneously evaluate markers for macrophages (CD68/CD163), neutrophils (CD66b), cytotoxic T-cells (CD8), B-cells (CD19/CD20), tumor cells (cytokeratin), PD-L1 expression, and DAPI. Immune cell distributions and their spatial relationships were quantified with HALO image analysis software (Indica Labs). Results: Nanostring analysis revealed increased differential expression of genes related to B-cell functions in HPV-positive HNSCC, such as MS4A1, CD79B, and CD27, which were significant at a Benjamini-Yekutieli adjusted p-value of <0.001. T-cell function genes (e.g. CTLA4 and LAG3) also had significantly increased expression in HPV-positive HNSCC compared to HPV-negative HNSCC. MIHC displayed increased CD8+ T-cell and CD19/CD20+ B-cell densities in the tumor region of HPV-positive HNSCC as opposed to HPV-negative HNSCC (p<0.01). There was a negative correlation in the densities of neutrophils and macrophages in the stroma region compared to density of T-cells in the tumor region in HPV-negative tumors (p<0.05), but not for HPV-positive tumors. Conclusions: HPV-positive HNSCC appears to have a B-cell and T-cell dominant gene expression profile with increased infiltration of these cells in the tumor region compared to HPV-negative HNSCC. The infiltration of CD8+ T-cells appears to be affected by myeloid cell burden in the stroma in HPV-negative HNSCC. The B-cell signature in HPV-positive HNSCC is particularly of interest, given that B-cells typically play a major role in resolving viral infections. Further analysis will involve correlating the differential patterns of gene expression with immune cell infiltration data to identify which immune cells have a more dominant effect on T-cell infiltration, and subsequently determine the effect on prognosis and response to ICI treatment. Citation Format: Hannan A. Qureshi, Xiaodong Zhu, Sylvia M. Lee, Eduardo Mendez, A. McGarry Houghton. Differential immune responses to HPV-positive and HPV-negative head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2841.