Tissue-resident memory features are linked to the magnitude of cytotoxic T cell responses in human lung cancer [NSCLC]

Therapies that boost the anti-tumor responses of cytotoxic lymphocytes (CTLs) have shown promise in the clinic. However, clinical responses to currently available immunotherapeutic agents vary considerably, for which the molecular basis is unclear. To date, unbiased transcriptomic studies of CTLs in human cancers have been performed in whole tumors or cells obtained from peripheral blood or metastatic sites of heavily pre-treated patients. We performed global transcriptional profiling of CTLs in tumors and adjacent non-tumor tissue from treatment-naïve patients with early stage lung cancer to define the molecular features associated with robustness of anti-tumor immune responses. We observed major differences in the transcriptional program of tumor-infiltrating CTLs that are shared across tumor subtypes. Pathway analysis revealed enrichment of genes in cell cycle, T cell receptor (TCR) activation and co-stimulation pathways, indicating tumor-driven expansion of presumed tumor antigen-specific CTLs. We also observed marked heterogeneity in the expression of molecules associated with TCR activation and immune checkpoints such as 4-1BB, PD1, TIM3, and their expression was positively correlated with the density of tumor-infiltrating CTLs. Interestingly, transcripts linked to tissue-resident memory cells (TRM), such as CD103, were enriched in tumors containing a high density of CTLs, and CTLs from CD103high tumors displayed features of enhanced cytotoxicity, implying better anti-tumor activity. In an independent cohort of 689 lung cancer patients, we confirmed that patients with CD103high (TRM rich) tumors survived significantly longer. In summary, we define the molecular fingerprint of tumor-infiltrating CTLs at the site of primary tumor and identify a number of novel targets that may be important in modulating the magnitude and specificity of anti-tumor immune responses in lung cancer.