Interferon-γ Drives Treg Fragility to Promote Anti-tumor Immunity.

Regulatory T cells (Tregs) are a barrier to anti-tumor immunity. Neuropilin-1 (Nrp1) is required to maintain intratumoral Treg stability and function but is dispensable for peripheral immune tolerance. Treg-restricted Nrp1 deletion results in profound tumor resistance due to Treg functional fragility. Thus, identifying the basis for Nrp1 dependency and the key drivers of Treg fragility could help to improve immunotherapy for human cancer. We show that a high percentage of intratumoral NRP1+ Tregs correlates with poor prognosis in melanoma and head and neck squamous cell carcinoma. Using a mouse model of melanoma where Nrp1-deficient (Nrp1-/-) and wild-type (Nrp1+/+) Tregs can be assessed in a competitive environment, we find that a high proportion of intratumoral Nrp1-/- Tregs produce interferon-γ (IFNγ), which drives the fragility of surrounding wild-type Tregs, boosts anti-tumor immunity, and facilitates tumor clearance. We also show that IFNγ-induced Treg fragility is required for response to anti-PD1, suggesting that cancer therapies promoting Treg fragility may be efficacious.

Immunotherapy for Head and Neck Squamous Cell Carcinoma: A Review of Current and Emerging Therapeutic Options.

Advances in the field of cancer immunotherapy have occurred rapidly over the past decade. Exciting results from clinical trials have led to new treatment options and improved survival for patients with a myriad of solid tumor pathologies. However, questions remain unanswered regarding duration and timing of therapy, combination regimens, appropriate biomarkers of disease, and optimal monitoring of therapeutic response. This article reviews emerging immunotherapeutic agents and significant clinical trials that have led to advancements in the field of immuno-oncology for patients with head and neck squamous cell carcinoma. IMPLICATIONS FOR PRACTICE: This review article summarizes recently developed agents that harness the immune system to fight head and neck squamous cell carcinoma. A brief review of the immune system and its role in cancer development is included. Recently completed and emerging therapeutic trials centering on the immune system and head and neck cancer are reviewed.

The Nasoseptal Flap for Reconstruction of Lateral Oropharyngectomy Defects: A Clinical Series.

OBJECTIVES/HYPOTHESIS: To study use of the nasoseptal flap (NSF) to reconstruct lateral transoral robotic surgery (TORS) oropharyngectomy defects. STUDY DESIGN: Retrospective case series. METHODS: A clinical series of six patients undergoing NSF reconstruction of lateral TORS oropharyngectomy defects was retrospectively studied. All patients underwent TORS for the treatment of intermediate-risk human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma of the lateral pharyngeal wall between January and June 2017. All patients underwent NSF reconstruction of lateral TORS defects with retrospective analysis of outcomes and complications. RESULTS: Six patients underwent NSF reconstruction of lateral TORS defects. Operative times decreased from 180 minutes to 90 minutes over the study period. There were two cases of partial flap dehiscence and partial necrosis. There were no major donor site complications. All patients had temporary nasal obstruction and crusting. Two experienced temporary aural fullness. In all patients, the lateral wall was mucosalized in 1-3 weeks. Cephalometric analysis of preoperative imaging revealed that patients with high-arched palates (>3 cm) and defect lengths that are longer than NSF flap lengths are poor candidates for this technique. CONCLUSIONS: This NSF is a vascularized, locoregional rotational flap that can reconstruct lateral TORS defects in salvages cases or those where the parapharyngeal carotid or mandibular bone are exposed. Postoperative morbidity is limited to temporary nasal dyspnea, aural fullness, and crusting. Preoperative imaging can determine which patient will have successful defect coverage. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:53-60, 2022.

Resistance to PD1 blockade in the absence of metalloprotease-mediated LAG3 shedding.

Mechanisms of resistance to cancer immunotherapy remain poorly understood. Lymphocyte activation gene-3 (LAG3) signaling is regulated by a disintegrin and metalloprotease domain-containing protein-10 (ADAM10)- and ADAM17-mediated cell surface shedding. Here, we show that mice expressing a metalloprotease-resistant, noncleavable LAG3 mutant (LAG3NC) are resistant to PD1 blockade and fail to mount an effective antitumor immune response. Expression of LAG3NC intrinsically perturbs CD4+ T conventional cells (Tconvs), limiting their capacity to provide CD8+ T cell help. Furthermore, the translational relevance for these observations is highlighted with an inverse correlation between high LAG3 and low ADAM10 expression on CD4+ Tconvs in the peripheral blood of patients with head and neck squamous cell carcinoma, which corresponded with poor prognosis. This correlation was also observed in a cohort of patients with skin cancers and was associated with increased disease progression after standard-of-care immunotherapy. These data suggest that subtle changes in LAG3 inhibitory receptor signaling can act as a resistance mechanism with a substantive effect on patient responsiveness to immunotherapy.

Biological mechanisms of immune escape and implications for immunotherapy in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy with high morbidity and mortality. Despite advances in cytotoxic therapies and surgical techniques, overall survival (OS) has not improved over the past few decades. This emphasises the need for intense investigation into novel therapies with good tumour control and minimal toxicity. Cancer immunotherapy has led this endeavour, attempting to improve tumour recognition and expand immune responses against tumour cells. While various forms of HNSCC immunotherapy are in preclinical trials, the most promising direction thus far has been with monoclonal antibodies (mAbs), targeting growth factor and immune checkpoint receptors. Preclinical and early phase trials have shown unprecedented efficacy with minimal adverse effects. This article will review biological mechanisms of immune escape and implications for immunotherapy in HNSCC.