Faculty Bibliography

Modern cancer immunotherapies represent a major shift in paradigm with respect to how we understand innate and adaptive responses to malignancy. Successful tumors co-opt normal immunosurveillance mechanisms by potent interactions between the tumor and local draining lymph nodes. Tumor cells mediate a complex and dynamic immunoediting procedure that results in increased vascular efflux into the draining lymphatics, an immunosuppressive microenvironment rich in regulatory T-lymphocytes, dysfunctional antigen presentation, and downregulation of normal effector lymphocyte responses. Our current approach to reversing this process for antitumor effect involves mainly systemic administration of immunotherapeutic agents, many of which have become standard of care in the management of a variety of cancers. Despite this, we are still learning how best to administer these drugs alone and in combination to maximize efficacy while minimizing adverse events. Increasing evidence suggests that comparable efficacy may be achieved by local administration of immunotherapies in the tumor or tumor-draining lymph nodes with substantially lower doses and better tolerability, even with combination therapy. Herein, we review the literature on intratumoral and intranodal immunotherapies in preclinical models and early-phase studies, with particular emphasis on approaches potentially suitable for translation to larger-scale clinical trials.

Background: There is growing appreciation for the role of tumordraining lymph nodes (TDLN) in the dynamic of immuno-editing orchestrated by non-small cell lung cancers (NSCLC). By comparing Tcell subsets and gene expression in TDLN and non-draining lymph nodes (NDLN), we aim to determine whether there is tumor-regional variation in immunophenotype. Method: Patients undergoing endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis/staging of NSCLC were recruited. Aspirates were obtained from TDLN (N1/N2 nodes with increased fluorodeoxyglucose-F-18 (FDG) avidity and/or enlarged >1cm) and NDLN (non-enlarged/non- FDG-avid N2/N3 nodes) along with peripheral blood. Samples were stained with fluorophore-conjugated antibodies (CD4-FITC, CD8-V450, CD25-PECy7, CD127-APCR700, CD45RO-PECF594) and analyzed by flow cytometry. CD4+CD25- and CD8+ effector T-cells (Teff) were sorted. Gene expression profiling was performed on sorted Teff using the NanostringTM platform to measure differential expression between TDLN and NDLNs. Result: We compared T-cell subpopulations in TDLN and paired NDLN from 16 subjects. There were significantly fewer CD4+ T-cells in TDLN vs NDLN (10.1% vs 28.9%, p=0.0039), with more Tregs (12.1% vs 7.3%, p=0.1563) suggesting a pattern of tumorregional immunosuppression in the TDLN. This was more consistent when tumor histology was adenocarcinoma compared to squamous cell cancer with respect to both depletion of Teff and higher proportion of Tregs (Fig 1). A more immunosuppressive TDLN phenotype was also observed with high tumor PD-L1 expression (>50%), with 36% fewer CD4+ T-cells in TDLN relative to paired NDLN when PD-L1 expression was high relative to just 3.2% fewer CD4+ T-cells with low PD-L1 expression. Gene expression in Teff has preliminarily demonstrated upregulation of genes mediating T-cell exhaustion (CTLA-4, PD-1, TGFb) and downregulation of co-stimulatory/recruitment factors (CD28, ICOS, ICAM2) in TDLN suggesting impaired activation of tumorregional Teff. Conclusion: Our findings suggest that TDLNs in patients with NSCLC display a tolerogenic phenotype, with more marked immunosuppression in the setting of adenocarcinoma and high tumor PD-L1 expression. (Figure Presented)

Establishing the etiology of exudative pleural effusions in the setting of an unrevealing pleural fluid analysis often requires biopsies from the parietal pleura. While closed pleural biopsy (CPB) has been a popular minimally-invasive approach, it has a poor diagnostic yield, barring a diagnosis of tuberculous pleurisy. Medical thoracoscopy (MT) is a minimally-invasive ambulatory procedure performed under local anesthesia or moderate sedation which allows for direct visualization of biopsy targets as well as simultaneous therapeutic interventions, including chemical pleurodesis and indwelling tunneled pleural catheter (ITPC) placement. The excellent yield and favorable safety profile of MT has led to it replacing CPB for many indications, particularly in the management of suspected malignant pleural effusions. As experience with MT amongst interventional pulmonologists has grown, there is an increased appreciation for its important role alongside percutaneous and surgical approaches in the diagnosis and treatment of pleural disease.