Epithelial-mesenchymal transition (EMT) is able to drive metastasis during progression of multiple cancer types, including non-small cell lung cancer (NSCLC). As resistance to immunotherapy has been associated with EMT and immune exclusion in melanoma, it is important to understand alterations to T-cell infiltration and the tumor microenvironment during EMT in lung adenocarcinoma and squamous cell carcinoma. We conducted an integrated analysis of the immune landscape in NSCLCs through EMT scores derived from a previously established 16 gene signature of canonical EMT markers. EMT was associated with exclusion of immune cells critical in the immune response to cancer, with significantly lower infiltration of CD4 T-cells in lung adenocarcinoma and CD4/CD8 T-cells in squamous cell carcinoma. EMT was also associated with increased expression of multiple immunosuppressive cytokines, including IL-10 and TGF-β. Furthermore, overexpression of targetable immune checkpoints, such as CTLA-4 and TIM-3 were associated with EMT in both NSCLCs. An association may exist between immune exclusion and EMT in NSCLC. Further investigation is merited as its mechanism is not completely understood and a better understanding of this association could lead to the development of biomarkers that could accurately predict response to immunotherapy.

Immunotherapy is emerging as a promising option for lung cancer treatment. Various endothelial adhesion molecules, such as integrin and selectin, as well as various cellular barrier molecules such as desmosome and tight junctions, regulate T-cell infiltration in the tumor microenvironment. However, little is known regarding how these molecules affect immune cells in patients with lung cancer. We demonstrated for the first time that overexpression of endothelial adhesion molecules and cellular barrier molecule genes was linked to differential infiltration of particular immune cells in non-small cell lung cancer. Overexpression of endothelial adhesion molecule genes is associated with significantly lower infiltration of activated CD4 and CD8 T-cells, but higher infiltration of activated B-cells and regulatory T-cells. In contrast, overexpression of desmosome genes was correlated with significantly higher infiltration of activated CD4 and CD8 T-cells, but lower infiltration of activated B-cells and regulatory T-cells in lung adenocarcinoma. This inverse relation of immune cells aligns with previous studies of tumor-infiltrating B-cells inhibiting T-cell activation. Although overexpression of endothelial adhesion molecule or cellular barrier molecule genes alone was not predictive of overall survival in our sample, these genetic signatures may serve as biomarkers of immune exclusion, or resistance to T-cell mediated immunotherapy.

Background: Association between T-effector (Teff) gene expression (GE), a marker of pre-existing immunity, and OS benefit with atezolizumab (antiePD-L1) was demonstrated in the Phase II study POPLAR of atezolizumab vs docetaxel in 2L+ NSCLC. We analyzed Teff GE association with atezolizumab efficacy in a larger Phase III study, OAK. Method: Patients with 2L+ NSCLC were randomized to receive atezolizumab or docetaxel. Teff signature was defined by 3 genes (PD-L1, CXCL9, and IFNg), and Teff GE was measured by averaging the normalized expression of each gene. Teff GE subgroups were defined by quartiles. PD-L1 expression was assessed using the SP142 IHC assay; the TC1/2/3 or IC1/2/3 subgroup had ! 1% PD-L1 expression on tumor cells (TC) or tumor-infiltrating immune cells (IC). Result: 753 of 850 patients from the OAK primary analysis constituted the biomarker evaluable population (BEP) for Teff GE. Expression of the Teff signature was associated with PD-L1 expression by IHC (P ¼ 7.3Â10 À45). Although no significant PFS benefit with atezolizumab vs docetaxel was observed in the BEP (HR, 0.94 [95% CI: 0.81, 1.10]) or the TC1/2/3 or IC1/2/3 subgroup (HR, 0.93 [95% CI: 0.76, 1.15]), a gradient of improved PFS benefit with atezolizumab was observed with increasing Teff GE. Significant PFS benefit occurred with ! median Teff GE cutoff (HR, 0.73 [95% CI: 0.58, 0.91]; Table). Teff GE also enriched for improved OS; however, a trend toward OS benefit was still observed in patients with low Teff GE (Table). Conclusion: This is the first demonstration of the association between markers of Teff biology and clinical outcomes with cancer immunotherapy in a randomized Phase III trial. Teff GE may reflect pre-existing immunity and be a more sensitive biomarker compared with PD-L1 IHC, identifying more patients (50% prevalence) likely to experience PFS benefit with atezolizumab.