Cancer cell-specific MHCII expression as a determinant of the immune infiltrate organization and function in the non-small cell lung cancer tumor microenvironment

Introduction In patients with non-small cell lung cancer (NSCLC), the prognostic significance of the tumor microenvironment (TME) immune composition has been demonstrated using single or dual-marker staining on sequential tissue sections. While these studies show that relative abundance and localization of immune cells are important parameters, deeper analyses of the NSCLC TME are necessary to refine the potential application of these findings to clinical care. Currently, the complex spatial relationships between cells of the NSCLC TME and potential drivers contributing to its immunologic composition remain unknown. Methods We employed multispectral quantitative imaging on the lung adenocarcinoma TME in 153 patients with resected tumors. On a single slide per patient, we evaluated the TME with markers for CD3, CD8, CD14, CD19, major histocompatibility complex II (MHCII), cytokeratin, and DAPI. Image analysis including tissue segmentation, phenotyping, and spatial localization were performed. Results Specimens where ≥5% of lung cancer cells expressed MHCII (MHCII hi TME) demonstrated increased levels of CD4 + and CD8 + T cell and CD14 + cell infiltration. In the MHCII hi TME, the immune infiltrate was closer to cancer cells and expressed an activated phenotype. Morphologic image analysis revealed cancer cells in the MHCII hi TME more frequently interfaced with CD4 + and CD8 + T cells. Patients with an MHCII hi TME experienced improved overall survival (p=0.046). Conclusions Lung cancer cell-specific expression of MHCII associates with levels of immune cell infiltration, spatial localization, and activation status within the TME. This suggest cancer cell-specific expression of MHCII may represent a biomarker for the immune system’s recognition and activation against the tumor.