IA19 Evaluating the Role of B Cells and Tertiary Lymphoid Structures in Lung Cancer Development and Progression

Abstract

Lung cancer is the leading cause of cancer death in both the United States and the world. Even with the best current treatments, the 5-year survival is only 15%. Immunotherapy has been impressively successful in multiple solid tumors, including non-small cell lung cancer (NSCLC), which, until recently, was always considered to be immune quiescent. Blockade of the inhibitory PD1:PDL1 pathway on CD8+ and CD4+ tumor-infiltrating lymphocytes (TILs) has revolutionized standard of care for NSCLC patients. Anti-PD1 can specifically target tumor cells without harming normal lung epithelial cells, which ultimately allows for fewer adverse events compared to standard chemotherapy or radiation. However, these approaches do not work in 80% of NSCLC patients; thus, a better understanding of the immune response prior to the development of cancer (heavy smokers and patients with chronic obstructive pulmonary disease [COPD]) compared to active disease (adenocarcinoma [LUAD] and squamous cell carcinoma [LUSC]) is necessary to develop new therapeutic approaches to enhance the antitumor immune response but also to assemble additional noninvasive, accurate screening methods for patients. The current immunotherapies for NSCLC patients do not consider or target B cells despite their predominance in the tumor microenvironment (TME) and key role in the adaptive immune response. Further, in NSCLC patients, current evidence suggests an antitumor role for B cells as they can generate tumor-specific antibodies, present antigens to CD4+ TILs, and are detected within tertiary lymphoid structures (TLS), which also correlate with better prognosis. TLS predominantly contain B cells, CD4+ T conventional cells, and CD14+ myeloid cells; however, unlike normal lymphoid tissues, i.e., lymph node or tonsil, TLS in cancer patients do not always have well-defined germinal centers (GCs). GCs are paramount for proper B-cell development and function. Thus, in order to successfully implement B-cell targeting into future immunotherapies, we must increase our understanding of B-cell function in TLS within premalignancy and overt cancer. We hypothesize that B cells help generate potent, long-term immune responses against lung tumor cells by educating CD4+ T cells in TLS and producing tumor-specific antibodies. Toward this hypothesis, we have evaluated B cells and TLS in premalignancy and overt cancer via single-cell RNA sequencing, advanced spectral cytometry (Cytek Aurora), and multispectral imaging (Vectra and Nanostring GeoMx platforms). These analyses have revealed key differences in B-cell infiltration and TLS formation as lung cancer develops and progresses. We have utilized our results to create an objective signature for TLS identification. Specifically, we have observed an increase in GC-like TLS as patients develop cancer. We have also begun to evaluate the ex vivo function of B cells in patient tumors via antigen presentation and antibody production assays. We have evidence for a differential function for B cells within the TME that correlates with activation status. Since B cells and TLS are great prognostic indicators in NSCLC patients, an improved objective measure of the different tiers of these structures and how they correlate with disease progression could offer new and viable (a) biomarkers to predict lung cancer progression, (b) targets for early immunotherapeutic intervention in COPD patients that might trigger better antitumor immunity as patients develop lung cancer, and (c) immunotherapeutic targets in patients with already established NSCLC.