Integrating multiplexed imaging and multiscale modeling identifies tumor phenotype conversion as a critical component of therapeutic T cell efficacy

Cancer progression is a complex process involving interactions that unfold across molecular, cellular, and tissue scales. These multiscale interactions have been difficult to measure and to simulate. Here, we integrated CODEX multiplexed tissue imaging with multiscale modeling software to model key action points that influence the outcome of T cell therapies with cancer. The initial phenotype of therapeutic T cells influences the ability of T cells to convert tumor cells to an inflammatory, anti-proliferative phenotype. This T cell phenotype could be preserved by structural reprogramming to facilitate continual tumor phenotype conversion and killing. One takeaway is that controlling the rate of cancer phenotype conversion is critical for control of tumor growth. The results suggest new design criteria and patient selection metrics for T cell therapies, call for a rethinking of T cell therapeutic implementation, and provide a foundation for synergistically integrating multiplexed imaging data with multiscale modeling of the cancer-immune interface. A record of this paper's transparent peer review process is included in the supplemental information.

Validation of the Melanoma Institute of Australia's Sentinel Lymph Node Biopsy Risk Prediction Tool for Cutaneous Melanoma

BACKGROUND

For patients with cutaneous melanoma, sentinel lymph node biopsy (SLNB) is used to stage regional lymph nodes pathologically and inform prognosis, treatment, and surveillance. To reduce unnecessary surgeries, predictive tools aim to identify those at lowest risk for node-positive disease. The Melanoma Institute of Australia (MIA)'s Prediction Tool for Sentinel Node Metastasis Risk estimates risk of a positive SLNB using patient age and primary melanoma Breslow depth, histologic subtype, ulceration, mitotic rate, and lymphovascular invasion.

METHODS

A single-institution validation was performed of the MIA Calculator with 982 cutaneous melanoma patients that included all relevant clinicopathologic factors and SLNB pathology outcomes. The study evaluated discrimination via receiver operating characteristic (ROC) curves, calibration via calibration plots, and clinical utility via decision curve analysis of the MIA model in various subgroups. The data were fit to MIA model parameters via a generalized linear model to assess the odds ratio of parameters in our dataset.

RESULTS

The Calculator demonstrated limited discrimination based on ROC curves (C-statistic, 0.709) and consistently underestimated risk of SLN positivity. It did not provide a net benefit over SLNB performed on all patients or reduce unnecessary procedures in the risk domain of 0% to 16%. Compared with the original development and validation cohorts, the current study cohort had thinner tumors and a larger proportion of acral melanomas.

CONCLUSIONS

The Calculator generally underestimated SLN positivity risk, including assessment in patients who would be counseled to forego SLNB based on a predicted risk lower than 5%. Recognition of the tool's current limitations emphasizes the need to refine it further for use in medical decision-making.

Racial Disparities in 30-day Readmissions after Surgery for Head and Neck Cancer

BACKGROUND

Native Hawaiians and other Pacific Islanders (NHPI) patients with head and neck cancer are often aggregated with Asian individuals despite evidence of heterogeneous health outcomes and mortality. The aim of this study was to determine the association of race with unplanned 30-day hospital readmission rate after head and neck surgery across the five federally recognized racial categories.

METHODS

This retrospective cohort study used a national hospital-based database and included patients ≥18 years old with diagnostically confirmed, nonmetastatic head and neck cancer of any subsite treated surgically between 2004 and 2017. The primary endpoint was unplanned readmission within 30 days of discharge after primary surgery.

RESULTS

A total of 365,834 patients were included who were predominantly White (87%), treated at academic cancer centers (47%), lower income (63%), with early-stage disease (60%), and with thyroid (47%) or oral cavity (23%) cancers. Median follow-up duration was 47 months. Of the 10,717 (3%) readmissions, 5,845 (1.6%) were unplanned. Adjusted for confounders and compared with White patients, NHPI patients had the highest likelihood of unplanned (aOR 2.07, 95%CI 1.16-3.40, p = 0.008) readmissions. Within the NHPI group, patients with lower income (aOR 4.27, 95%CI 1.28-20.4, p = 0.035) and those residing in an urban or rural area (aOR 7.42, 95%CI 1.14-49.5, p = 0.034) were more likely to be readmitted.

CONCLUSIONS

NHPI patients with head and neck cancers experience significantly higher 30-day readmissions following definitive surgical treatment. These results highlight the importance of racial disaggregation in clinical studies.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1282-1287, 2024.

T cell-mediated curation and restructuring of tumor tissue coordinates an effective immune response

Antigen-specific T cells traffic to, are influenced by, and create unique cellular microenvironments. Here we characterize these microenvironments over time with multiplexed imaging in a melanoma model of adoptive T cell therapy and human patients with melanoma treated with checkpoint inhibitor therapy. Multicellular neighborhood analysis reveals dynamic immune cell infiltration and inflamed tumor cell neighborhoods associated with CD8+ T cells. T cell-focused analysis indicates T cells are found along a continuum of neighborhoods that reflect the progressive steps coordinating the anti-tumor immune response. More effective anti-tumor immune responses are characterized by inflamed tumor-T cell neighborhoods, flanked by dense immune infiltration neighborhoods. Conversely, ineffective T cell therapies express anti-inflammatory cytokines, resulting in regulatory neighborhoods, spatially disrupting productive T cell-immune and -tumor interactions. Our study provides in situ mechanistic insights into temporal tumor microenvironment changes, cell interactions critical for response, and spatial correlates of immunotherapy outcomes, informing cellular therapy evaluation and engineering.

Spatial subsetting enables integrative modeling of oral squamous cell carcinoma multiplex imaging data

Oral squamous cell carcinoma (OSCC), a prevalent and aggressive neoplasm, poses a significant challenge due to poor prognosis and limited prognostic biomarkers. Leveraging highly multiplexed imaging mass cytometry, we investigated the tumor immune microenvironment (TIME) in OSCC biopsies, characterizing immune cell distribution and signaling activity at the tumor-invasive front. Our spatial subsetting approach standardized cellular populations by tissue zone, improving feature reproducibility and revealing TIME patterns accompanying loss-of-differentiation. Employing a machine-learning pipeline combining reliable feature selection with multivariable modeling, we achieved accurate histological grade classification (AUC = 0.88). Three model features correlated with clinical outcomes in an independent cohort: granulocyte MAPKAPK2 signaling at the tumor front, stromal CD4+ memory T cell size, and the distance of fibroblasts from the tumor border. This study establishes a robust modeling framework for distilling complex imaging data, uncovering sentinel characteristics of the OSCC TIME to facilitate prognostic biomarkers discovery for recurrence risk stratification and immunomodulatory therapy development.

Loss of p53-DREAM-mediated repression of cell cycle genes as a driver of lymph node metastasis in head and neck cancer

BACKGROUND

The prognosis for patients with head and neck cancer (HNC) is poor and has improved little in recent decades, partially due to lack of therapeutic options. To identify effective therapeutic targets, we sought to identify molecular pathways that drive metastasis and HNC progression, through large-scale systematic analyses of transcriptomic data.

METHODS

We performed meta-analysis across 29 gene expression studies including 2074 primary HNC biopsies to identify genes and transcriptional pathways associated with survival and lymph node metastasis (LNM). To understand the biological roles of these genes in HNC, we identified their associated cancer pathways, as well as the cell types that express them within HNC tumor microenvironments, by integrating single-cell RNA-seq and bulk RNA-seq from sorted cell populations.

RESULTS

Patient survival-associated genes were heterogenous and included drivers of diverse tumor biological processes: these included tumor-intrinsic processes such as epithelial dedifferentiation and epithelial to mesenchymal transition, as well as tumor microenvironmental factors such as T cell-mediated immunity and cancer-associated fibroblast activity. Unexpectedly, LNM-associated genes were almost universally associated with epithelial dedifferentiation within malignant cells. Genes negatively associated with LNM consisted of regulators of squamous epithelial differentiation that are expressed within well-differentiated malignant cells, while those positively associated with LNM represented cell cycle regulators that are normally repressed by the p53-DREAM pathway. These pro-LNM genes are overexpressed in proliferating malignant cells of TP53 mutated and HPV + ve HNCs and are strongly associated with stemness, suggesting that they represent markers of pre-metastatic cancer stem-like cells. LNM-associated genes are deregulated in high-grade oral precancerous lesions, and deregulated further in primary HNCs with advancing tumor grade and deregulated further still in lymph node metastases.

CONCLUSIONS

In HNC, patient survival is affected by multiple biological processes and is strongly influenced by the tumor immune and stromal microenvironments. In contrast, LNM appears to be driven primarily by malignant cell plasticity, characterized by epithelial dedifferentiation coupled with EMT-independent proliferation and stemness. Our findings postulate that LNM is initially caused by loss of p53-DREAM-mediated repression of cell cycle genes during early tumorigenesis.

Oral cavity cancer in young, non-smoking, and non-drinking patients: A contemporary review

Oral squamous cell carcinoma (OSCC) in non-smoking and non-drinking (NSND) individuals appears to be distinct from the traditional head and neck squamous cell carcinoma (HNSCC). The incidence of this subset is increasing, as are the number of studies examining its characteristics. NSND OSCC individuals tend to be younger (<45 years) compared to traditional HNSCC patients. The proportion of females in the NSND OSCC cohort is also higher. The tongue is the predominantly affected subsite. Studies have revealed several gene mutations and unique epigenomic profiles but no definitive genetic etiology. Transcriptomic analysis has not found any causative viral agents. Other proposed etiologies include chronic dental trauma, microbiome abnormalities, marijuana consumption, and genetic disorders. There are international efforts to determine the relative prognostic outcome of this unique cohort, but no consensus has been reached. Here, we review the incidence, demographics, subsite, possible etiologies, prognosis, and therapy implications of the NSND OSCC cohort.

Toll-like Receptor Agonists Are Unlikely to Provide Benefits in Head and Neck Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Recurrent and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) has poor survival rates. Immunotherapy is the standard of care for R/M HNSCC, but objective responses occur in a minority of patients. Toll-like receptor (TLR) agonists promote antitumor immune responses and have been explored in clinical trials.

METHODS

A search for clinical trials using TLR agonists in HNSCC was performed under PRISMA guidelines. Data on patient characteristics, safety, and efficacy were collected and analyzed.

RESULTS

Three phase 1b trials with 40 patients and three phase 2 trials with 352 patients studying TLR8 and TLR9 agonists in combination with other treatment regimens for HNSCC were included. In phase 2 trials, there was no significant change in the objective response rate (RR = 1.13, CI 0.80-1.60) or association with increased grade 3+ adverse events (RR = 0.91, CI 0.76-1.11) associated with TLR agonist use.

CONCLUSION

TLR agonists do not appear to provide additional clinical benefits or increase adverse events in the treatment of HNSCC. Given these results across multiple clinical trials and drug regimens, it is unlikely that additional trials of TLR agonists will demonstrate clinical benefits in HNSCC.

Targeting KDM2A Enhances T-cell Infiltration in NSD1-Deficient Head and Neck Squamous Cell Carcinoma

In head and neck squamous cell carcinoma (HNSCC), a significant proportion of tumors have inactivating mutations in the histone methyltransferase NSD1. In these tumors, NSD1 inactivation is a driver of T-cell exclusion from the tumor microenvironment (TME). A better understanding of the NSD1-mediated mechanism regulating infiltration of T cells into the TME could help identify approaches to overcome immunosuppression. Here, we demonstrated that NSD1 inactivation results in lower levels of H3K36 dimethylation and higher levels of H3K27 trimethylation, the latter being a known repressive histone mark enriched on the promoters of key T-cell chemokines CXCL9 and CXCL10. HNSCC with NSD1 mutations had lower levels of these chemokines and lacked responses to PD-1 immune checkpoint blockade. Inhibition of KDM2A, the primary lysine demethylase that is selective for H3K36, reversed the altered histone marks induced by NSD1 loss and restored T-cell infiltration into the TME. Importantly, KDM2A suppression decreased growth of NSD1-deficient tumors in immunocompetent, but not in immunodeficient, mice. Together, these data indicate that KDM2A is an immunotherapeutic target for overcoming immune exclusion in HNSCC.

SIGNIFICANCE

The altered epigenetic landscape of NSD1-deficient tumors confers sensitivity to inhibition of the histone-modifying enzyme KDM2A as an immunotherapeutic strategy to stimulate T-cell infiltration and suppress tumor growth.

SMYD3 represses tumor-intrinsic interferon response in HPV-negative squamous cell carcinoma of the head and neck

Cancers often display immune escape, but the mechanisms are incompletely understood. Herein, we identify SMYD3 as a mediator of immune escape in human papilloma virus (HPV)-negative head and neck squamous cell carcinoma (HNSCC), an aggressive disease with poor response to immunotherapy with pembrolizumab. SMYD3 depletion induces upregulation of multiple type I interferon (IFN) response and antigen presentation machinery genes in HNSCC cells. Mechanistically, SMYD3 binds to and regulates the transcription of UHRF1, encoding for a reader of H3K9me3, which binds to H3K9me3-enriched promoters of key immune-related genes, recruits DNMT1, and silences their expression. SMYD3 further maintains the repression of immune-related genes through intragenic deposition of H4K20me3. In vivo, Smyd3 depletion induces influx of CD8+ T cells and increases sensitivity to anti-programmed death 1 (PD-1) therapy. SMYD3 overexpression is associated with decreased CD8 T cell infiltration and poor response to neoadjuvant pembrolizumab. These data support combining SMYD3 depletion strategies with checkpoint blockade to overcome anti-PD-1 resistance in HPV-negative HNSCC.

Abstract 3469: Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immune tolerance

The majority of cancer-associated deaths result from distant organ metastasis, yet the mechanisms that enable this process remain poorly understood. For most solid tumors, colonization of regional or distant lymph nodes (LNs) typically precedes the formation of distant organ metastases, yet it remains unclear whether LN metastasis plays a functional role in disease progression. LNs are major sites of anti-tumor lymphocyte education, including in the context of immunotherapy, yet LN metastasis frequently correlates with further disease progression. Here, we find that LN metastasis represents a critical step in tumor progression through the capacity of such metastases to induce tumor-specific immune tolerance in a manner that promotes further dissemination of tumors to distant organs. Using an in vivo passaging approach of a non-metastatic syngeneic melanoma, we generated 300 unique cell lines exhibiting varying degrees of LN metastatic capacity. We show that the presence of these LN metastases enables distant organ seeding of metastases in a manner that the parental tumor cannot, and this effect is eliminated in mice lacking an adaptive immune response. Furthermore, this promotion of distant seeding by LN metastases is tumor specific. Using flow cytometry and single-cell sequencing to perform comprehensive immune profiling, we identify multiple cellular mediators of tolerance. In particular, we find that LN metastases have the capacity to both resist NK cell cytotoxicity and induce regulatory T cells (Tregs). Furthermore, depletion of NK cells in vivo enables non-metastatic tumors to disseminate to LNs, and ablation of Tregs using FoxP3-DTR mice eliminates the occurrence of lymphatic metastases. Adoptive transfer of Tregs from the LNs of mice bearing LN metastasis to naïve mice facilitates metastasis in a manner that Tregs from mice without LN metastases cannot, and we find that these Tregs are induced in an antigen-specific manner. Whole exome sequencing revealed that neither the metastatic proclivity nor immunosuppression evolve through the acquisition of driver mutations, loss of neoantigens, loss of MHC class I presentation, or decreases in melanoma antigen expression. Rather, by RNA-seq and ATAC-seq, we show that a conserved interferon signaling axis is upregulated in LN metastases and is rendered stable through epigenetic reprogramming of chromatin accessibility resulting from chronic exposure to interferons in vivo. Furthermore, using CRISPR/Cas9, we find that these pathways are required for LN metastatic seeding, and validate their conserved significance in additional mouse models of pancreatic ductal adenocarcinoma and head and neck squamous cell carcinoma and humans with LN metastatic disease. Together, these findings demonstrate a critical role for LN metastasis in promoting tumor-specific immunosuppression.

Citation Format: Nathan E. Reticker-Flynn, Weiruo Zhang, Julia A. Belk, Pamela A. Basto, Andrew J. Gentles, John B. Sunwoo, Ansuman T. Satpathy, Sylvia K. Plevritis, Edgar G. Engleman. Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immune tolerance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3469.

NFE2L2 Mutations Enhance Radioresistance in Head and Neck Cancer by Modulating Intratumoral Myeloid Cells

Radiotherapy (RT) is one of the primary treatments of head and neck squamous cell carcinoma (HNSCC), which has a high-risk of locoregional failure (LRF). Presently, there is no reliable predictive biomarker of radioresistance in HNSCC. Here, we found that mutations in NFE2L2, which encodes Nrf2, are associated with a significantly higher rate of LRF in patients with oral cavity cancer treated with surgery and adjuvant (chemo)radiotherapy but not in those treated with surgery alone. Somatic mutation of NFE2L2 led to Nrf2 activation and radioresistance in HNSCC cells. Tumors harboring mutant Nrf2E79Q were substantially more radioresistant than tumors with wild-type Nrf2 in immunocompetent mice, whereas the difference was diminished in immunocompromised mice. Nrf2E79Q enhanced radioresistance through increased recruitment of intratumoral polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) and reduction of M1-polarized macrophages. Treatment with the glutaminase inhibitor CB-839 overcame the radioresistance induced by Nrf2E79Q or Nrf2E79K. RT increased expression of PMN-MDSC-attracting chemokines, including CXCL1, CXLC3, and CSF3, in Nrf2E79Q-expressing tumors via the TLR4, which could be reversed by CB-839. This study provides insights into the impact of NFE2L2 mutations on radioresistance and suggests that CB-839 can increase radiosensitivity by switching intratumoral myeloid cells to an antitumor phenotype, supporting clinical testing of CB-839 with RT in HNSCC with NFE2L2 mutations.

SIGNIFICANCE

NFE2L2 mutations are predictive biomarkers of radioresistance in head and neck cancer and confer sensitivity to glutaminase inhibitors to overcome radioresistance.

Abstract PR013: Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immune tolerance

The majority of cancer-associated deaths result from distant organ metastasis, yet the mechanisms that enable this process remain poorly understood. For most solid tumors, colonization of regional or distant lymph nodes (LNs) typically precedes the formation of distant organ metastases, yet it remains unclear whether LN metastasis plays a functional role in disease progression. LNs are major sites of anti-tumor lymphocyte education, including in the context of immunotherapy, yet LN metastasis frequently correlates with further disease progression. Here, we find that LN metastasis represents a critical step in tumor progression through the capacity of such metastases to induce tumor-specific immune tolerance in a manner that promotes further dissemination of tumors to distant organs. Using an in vivo passaging approach of a non-metastatic syngeneic melanoma, we generated 300 unique cell lines exhibiting varying degrees of LN metastatic capacity. We show that the presence of these LN metastases enables distant organ seeding of metastases in a manner that the parental tumor cannot, and this effect is eliminated in mice lacking an adaptive immune response. Furthermore, this promotion of distant seeding by LN metastases is tumor specific. Using flow cytometry and single-cell sequencing to perform comprehensive immune profiling, we identify multiple cellular mediators of tolerance. In particular, we find that LN metastases have the capacity to both resist NK cell cytotoxicity and induce regulatory T cells (Tregs). Furthermore, depletion of NK cells in vivo enables non-metastatic tumors to disseminate to LNs, and ablation of Tregs using FoxP3-DTR mice eliminates the occurrence of lymphatic metastases. Adoptive transfer of Tregs from the LNs of mice bearing LN metastasis to naïve mice facilitates metastasis in a manner that Tregs from mice without LN metastases cannot, and we find that these Tregs are induced in an antigen-specific manner. Whole exome sequencing revealed that neither the metastatic proclivity nor immunosuppression evolve through the acquisition of driver mutations, loss of neoantigens, loss of MHC class I presentation, or decreases in melanoma antigen expression. Rather, by RNA-seq and ATAC-seq, we show that a conserved interferon signaling axis is upregulated in LN metastases and is rendered stable through epigenetic reprogramming of chromatin accessibility resulting from chronic exposure to interferons in vivo. Furthermore, using CRISPR/Cas9, we find that these pathways are required for LN metastatic seeding, and validate their conserved significance in additional mouse models of pancreatic ductal adenocarcinoma and head and neck squamous cell carcinoma and humans with LN metastatic disease. Together, these findings demonstrate a critical role for LN metastasis in promoting tumor-specific immunosuppression.

Citation Format: Nathan E. Reticker-Flynn, Weiruo Zhang, Julia A. Belk, Pamela A. Basto, Andrew J. Gentles, John B. Sunwoo, Ansuman K. Satpathy, Sylvia K. Plevritis, Edgar G. Engleman. Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immune tolerance [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr PR013.

Genomic Immune Evasion: Diagnostic and Therapeutic Opportunities in Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell cancers (HNSCCs) represent a diverse group of tumors emerging within different mucosal surfaces of the oral cavity, nasopharynx, oropharynx, larynx, and hypopharynx. HNSCCs share common clinical risk factors and genomic features, including smoking, alcohol, age, male sex, aneuploidy, and TP53 mutations. Viral initiating and contributing events are increasingly recognized in HNSCCs. While both Epstein-Barr Virus (EBV) and human papilloma virus (HPV) are observed, EBV is more frequently associated with nasopharyngeal cancers whereas HPV is associated with oropharyngeal cancers. HNSCCs are associated with high tumor mutational burden and loss of tumor suppressor gene function, especially in TP53 and X-linked genes. Multiple lines of evidence suggest that HNSCCs are subject to immunologic surveillance and immune-induced evolutionary pressure that correlate with negative clinical outcomes. This review will discuss genomic mechanisms related to immune-mediated pressures and propose prognostic and therapeutic implications of detectable immune escape mechanisms that drive tumorigenesis and disease progression.

NSD1 mutations deregulate transcription and DNA methylation of bivalent developmental genes in Sotos syndrome

Sotos syndrome (SS), the most common overgrowth with intellectual disability (OGID) disorder, is caused by inactivating germline mutations of NSD1, which encodes a histone H3 lysine 36 methyltransferase. To understand how NSD1 inactivation deregulates transcription and DNA methylation (DNAm), and to explore how these abnormalities affect human development, we profiled transcription and DNAm in SS patients and healthy control individuals. We identified a transcriptional signature that distinguishes individuals with SS from controls and was also deregulated in NSD1-mutated cancers. Most abnormally expressed genes displayed reduced expression in SS; these downregulated genes consisted mostly of bivalent genes and were enriched for regulators of development and neural synapse function. DNA hypomethylation was strongly enriched within promoters of transcriptionally deregulated genes: overexpressed genes displayed hypomethylation at their transcription start sites while underexpressed genes featured hypomethylation at polycomb binding sites within their promoter CpG island shores. SS patients featured accelerated molecular aging at the levels of both transcription and DNAm. Overall, these findings indicate that NSD1-deposited H3K36 methylation regulates transcription by directing promoter DNA methylation, partially by repressing polycomb repressive complex 2 (PRC2) activity. These findings could explain the phenotypic similarity of SS to OGID disorders that are caused by mutations in PRC2 complex-encoding genes.

BASECAMP-1: Leveraging human leukocyte antigen (HLA) loss of heterozygosity (LOH) in solid tumors by next-generation sequencing (NGS) to identify patients with relapsed solid tumor for future logic-gated Tmod CAR T-cell therapy

TPS2676

Background: Solid tumors comprise > 90% of cancers. Metastatic colorectal cancer, non-small cell lung cancer, and pancreatic cancer are among the leading causes of cancer-related mortality (5-year overall survival: 14%, 6%, and 3%, respectively) (ACS. 2021). Chimeric antigen receptor (CAR) T-cell therapy has demonstrated clinical efficacy in hematologic malignancies (Neelapu S. et al. N Engl J Med. 2017). Translating engineered T-cell therapies to solid tumors has proven to be challenging due to a lack of tumor-specific targets that can discriminate cancer cells from normal cells. Previous studies using carcinoembryonic antigen (CEA) T-cell receptors and mesothelin (MSLN) CARs resulted in dose-limiting on-target, off-tumor toxicities (Parkhurst M, et al. Mol Ther. 2011; Tanyi J. Cellicon Valley '21). To create a therapeutic safety window, Tmod CAR T-cell therapy utilizes dual-signaling receptors to create a robust NOT logic gate capable of killing tumor cells, while leaving healthy cells intact (Hamburger A, et al. Mol Immunol. 2020). The 2 receptors in Tmod CAR T-cell therapy comprise an activator that recognizes an antigen on the surface of tumor cells that may also be present on normal cells, such as CEA and MSLN, and a blocker that recognizes a second surface antigen from an allele lost only in tumor cells. The frequency of HLA LOH among advanced GI solid tumor cancers in the Tempus real-world dataset is 16.3% with a range of 15.6%-20.8% between colorectal, pancreatic, and gastroesophageal tumors (Hecht R. et al. ASCO-GI 2022. Abstract #190). As such, HLA LOH offers a definitive tumor versus normal discriminator target for CAR T-cell therapy. Different activator/blocker combinations can be engineered with the Tmod platform technology and may be applied to T cells and natural killer cells in autologous and allogeneic settings. BASECAMP-1 is a currently enrolling observational study with key objectives of 1) To identify patients with somatic HLA LOH eligible for Tmod CAR T-cell therapy, and 2) To obtain leukapheresis and feasibility for the future EVEREST Tmod CAR T-cell trial. Methods: BASECAMP-1 (NCT04981119) patient eligibility has 2 parts: 1) Patients will be initially screened to identify germline HLA-A*02 heterozygosity by central NGS. If HLA-A*02 heterozygosity is confirmed, primary archival tumor tissue will be analyzed for somatic mutations by xT-Onco NGS testing. 2) If the tumor demonstrates HLA-A*02 LOH and the patient is eligible after screening, the patient will undergo leukapheresis. Banked T cells will be available for the autologous EVEREST Tmod CAR T-cell therapy interventional study to reduce waiting time at relapse. Clinical trial information: NCT04981119.

Lymph node colonization induces tumor-immune tolerance to promote distant metastasis

For many solid malignancies, lymph node (LN) involvement represents a harbinger of distant metastatic disease and, therefore, an important prognostic factor. Beyond its utility as a biomarker, whether and how LN metastasis plays an active role in shaping distant metastasis remains an open question. Here, we develop a syngeneic melanoma mouse model of LN metastasis to investigate how tumors spread to LNs and whether LN colonization influences metastasis to distant tissues. We show that an epigenetically instilled tumor-intrinsic interferon response program confers enhanced LN metastatic potential by enabling the evasion of NK cells and promoting LN colonization. LN metastases resist T cell-mediated cytotoxicity, induce antigen-specific regulatory T cells, and generate tumor-specific immune tolerance that subsequently facilitates distant tumor colonization. These effects extend to human cancers and other murine cancer models, implicating a conserved systemic mechanism by which malignancies spread to distant organs.

Overcoming barriers to solid tumor immunotherapy using natural killer cell therapies designed to mimic intraepithelial group 1 innate lymphoid cells

Our work aims to design cell-based immunotherapies for maximum solid tumor efficacy by leveraging insights from tissue-resident cells and single-cell RNA sequencing of innate immune cell subsets present within patient tumors. We discovered that by co-culturing peripheral blood natural killer cells (pbNKs) with irradiated epithelial tumor cells, we induced high expression of surface integrins, increased cytotoxicity and IFNg production, decreased sensitivity to TGFb, and significantly enhanced solid tumoroid infiltration. The cells were profiled using CyTOF and we determined that they closely resembled intraepithelial group 1 innate lymphoid cells, so we refer to them as ieILC1-like cells. We quantified the cytotoxicity of ieILC1-like cells against a variety of target cell lines and determined that they are broadly cytotoxic and capable of antibody-dependent cellular cytotoxicity, which was assessed using cetuximab. Tumor-infiltrating capacity was modeled using 3D tumoroids grown from single-cell suspensions of epithelial tumor cell lines in basement membrane extracts; ieILC1-like NK cells or pbNK cells were fluorescently labeled, added to tumoroids, and imaged using confocal microscopy. We stimulated the cells in the presence or absence of overnight TGFb exposure to determine the extent of TGFb-mediated immunosuppression. ieILC1-like cells were more resistant to TGFb and produced significantly more IFNg after stimulation than their pbNK counterparts. Preliminary in vivo work indicates that ieILC1-like cells perform comparably to K562-expanded NK cells. Thus, ieILC1-like NK cells represent a novel class of cell therapy that are more capable of infiltrating solid tumors and resisting their immunosuppressive cues.

Supported by NIH R35DE030054.

Emerging NK cell therapies for cancer and the promise of next generation engineering of iPSC-derived NK cells

Adoptive cell therapy is a rapidly advancing approach to cancer immunotherapy that seeks to facilitate antitumor responses by introducing potent effector cells into the tumor microenvironment. Expanded autologous T cells, particularly T cells with engineered T cell receptors (TCR) and chimeric antigen receptor-T cells have had success in various hematologic malignancies but have faced challenges when applied to solid tumors. As a result, other immune subpopulations may provide valuable and orthogonal options for treatment. Natural killer (NK) cells offer the possibility of significant tumor clearance and recruitment of additional immune subpopulations without the need for prior antigen presentation like in T or B cells that could require removal of endogenous antigen specificity mediated via the T cell receptor (TCR and/or the B ecll receptor (BCR). In recent years, NK cells have been demonstrated to be increasingly important players in the immune response against cancer. Here, we review multiple avenues for allogeneic NK cell therapy, including derivation of NK cells from peripheral blood or umbilical cord blood, the NK-92 immortalized cell line, and induced pluripotent stem cells (iPSCs). We also describe the potential of engineering iPSC-derived NK cells and the utility of this platform. Finally, we consider the benefits and drawbacks of each approach and discuss recent developments in the manufacturing and genetic or metabolic engineering of NK cells to have robust and prolonged antitumor responses in preclinical and clinical settings.

The microdissected gene expression landscape of nasopharyngeal cancer reveals vulnerabilities in FGF and noncanonical NF-κB signaling

Nasopharyngeal cancer (NPC) is an Epstein-Barr virus (EBV)-positive epithelial malignancy with an extensive inflammatory infiltrate. Traditional RNA-sequencing techniques uncovered only microenvironment signatures, while the gene expression of the tumor epithelial compartment has remained a mystery. Here, we use Smart-3SEQ to prepare transcriptome-wide gene expression profiles from microdissected NPC tumors, dysplasia, and normal controls. We describe changes in biological pathways across the normal to tumor spectrum and show that fibroblast growth factor (FGF) ligands are overexpressed in NPC tumors, while negative regulators of FGF signaling, including SPRY1, SPRY2, and LGALS3, are down-regulated early in carcinogenesis. Within the NF-κB signaling pathway, the critical noncanonical transcription factors, RELB and NFKB2, are enriched in the majority of NPC tumors. We confirm the responsiveness of EBV-positive NPC cell lines to targeted inhibition of these pathways, reflecting the heterogeneity in NPC patient tumors. Our data comprehensively describe the gene expression landscape of NPC and unravel the mysteries of receptor tyrosine kinase and NF-κB pathways in NPC.

High-resolution positron emission microscopy of patient-derived tumor organoids

Tumor organoids offer new opportunities for translational cancer research, but unlike animal models, their broader use is hindered by the lack of clinically relevant imaging endpoints. Here, we present a positron-emission microscopy method for imaging clinical radiotracers in patient-derived tumor organoids with spatial resolution 100-fold better than clinical positron emission tomography (PET). Using this method, we quantify 18F-fluorodeoxyglucose influx to show that patient-derived tumor organoids recapitulate the glycolytic activity of the tumor of origin, and thus, could be used to predict therapeutic response in vitro. Similarly, we measure sodium-iodine symporter activity using 99mTc- pertechnetate and find that the iodine uptake pathway is functionally conserved in organoids derived from thyroid carcinomas. In conclusion, organoids can be imaged using clinical radiotracers, which opens new possibilities for identifying promising drug candidates and radiotracers, personalizing treatment regimens, and incorporating clinical imaging biomarkers in organoid-based co-clinical trials.

Abstract 555: Longitudinal exome-scale liquid biopsy monitoring of evolving therapeutic resistance mechanisms in head and neck squamous cell carcinoma patients receiving anti-PD-1 therapy

Background Typical liquid biopsy panels capture a relatively small number of variants, and likely under-represent the heterogeneity of resistance in late-stage cancers. This reduced scope can result in overlooked therapeutic biomarkers which respond dynamically to treatment, as well as potentially missed resistance mechanisms and pathway-level events. To address the challenges associated with identifying multiple concurrent heterogeneous resistance mechanisms in individual patients, we evaluated longitudinal whole exome sequencing of cell free DNA (cfDNA) and solid tumor biopsies from head and neck squamous cell carcinoma (HNSCC) patients that received anti-PD1 therapy. Using this approach, we identified evolving variant and pathway-level resistance mechanisms in cfDNA, as a complement to tumor biopsy derived information, and identified differences in putative neoantigens found in tissue and cfDNA.

Methods Pre- and post-intervention matched tumor, normal and plasma samples were obtained from a pilot cohort of 13 patients with HNSCC. Following baseline sample collection, all patients received a single dose of nivolumab. The primary tumor was then resected, approximately one month later when possible, or a second biopsy was collected where resection was impractical. Paired tumor and normal samples were profiled using ImmunoID NeXTTM, an augmented exome/transcriptome platform and analysis pipeline. Exome-scale cfDNA profiling of matched plasma samples was performed using the NeXT Liquid BiopsyTM platform to detect somatic variants. Data from these two platforms were then compared with corresponding clinical findings.

Results We observed a rapid evolution of the tumor microenvironment and disease mutation profile following therapy, with strong concordance detected between plasma and tumor variants at each timepoint. Post-therapy interrogation of cfDNA revealed dynamic changes in numerous oncogenes and clinically relevant pathways, such as ERK1/2 and MAPK, that were not observed in solid tumor. These findings suggest that single-lesion biopsy of the primary tumor misses co-occurring, clinically relevant resistance alterations. Median post-treatment neoantigen count was reduced in solid tumor, but increased in cfDNA. HLA-specific loss of heterozygosity (LOH) was identified in a number of subjects, likely resulting in reduced neoepitope presentation in those cases.

Conclusions Exome-wide somatic events were reliably detected in cfDNA, providing additional potential biomarkers to complement those identified in solid tumor. As we increase our cohort size, we expect that identification of biomarkers from both exome scale tissue biopsy and cfDNA will provide a more comprehensive view into therapeutic response and resistance mechanisms in HNSCC patients missed with typical liquid biopsy panels.

Citation Format: Charles W. Abbott, Nikita Bedi, Simo V. Zhang, Josette Northcott, Robin LI, Rachel Marty Pyke, Eric Levy, Rebecca Chernock, Mena Mansour, A. Dimitrios Colevas, John Lyle, John B. Sunwoo, Sean Boyle, Richard Chen. Longitudinal exome-scale liquid biopsy monitoring of evolving therapeutic resistance mechanisms in head and neck squamous cell carcinoma patients receiving anti-PD-1 therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 555.

Association of HLA loss of heterozygosity with allele-specific neoantigen expansion in response to immunotherapy

e18030

Background: Human leukocyte antigen loss of heterozygosity (HLA LOH) restricts immune recognition of tumors by limiting the major histocompatibility complex (MHC) presentation of neoantigens to T cells and correlates with reduced response to immune checkpoint blockade therapy (ICB) in non-small cell lung cancer. To explore the mechanism behind the impairment of HLA LOH on ICB, we analyzed the relationship between the antigen presentation pathway, neoantigen presentation and response to ICB in a head and neck squamous cell carcinoma (HNSCC) cohort. Methods: Following baseline sample collection, a cohort of 14 HNSCC patients recieved a single dose of PD-1 inhibitor. The primary tumor mass was definitively resected approximately one month later. If resection was impractical, a second biopsy was taken. Response to therapy was evaluated using RECIST criteria. Each pre- and post-intervention tumor sample and normal PBMC sample were profiled using Personalis’ ImmunoID NeXT Platform, an HLA-enhanced exome/transcriptome platform. HLA LOH was detected using a digital PCR validated machine learning algorithm (DASH). Neoantigen presentation was computationally predicted using a machine learning algorithm (SHERPATM) trained on mono-allelic immunopeptidomics data. Results: We found that 50% of the HNSCC cohort had HLA LOH, a larger percentage than in a large pan-cancer cohort (23%, n=611) and a distinct HNSCC cohort (40%, n=20). Further, two patients had B2M LOH and one patient had a deleterious mutation in an HLA allele. Despite the high frequency of somatic alteration in the antigen presentation pathway, we did not find an association between HLA LOH and ICB response. However, if HLA LOH was still shaping tumor evolution in response to ICB, we would expect to see immune pressure against subclonal tumor populations with neoantigens presentable by the retained HLA alleles but not the deleted HLA alleles. Indeed, we found that significantly more novel post-treatment neoantigens were predicted to bind to deleted HLA alleles compared to their homologous alleles (p=0.045). Conclusions: Given the high prevalence of HLA LOH across tumor types, a greater understanding is needed regarding the impact of HLA LOH on tumor evolution during ICB treatment. Though HLA LOH does not correlate with response to ICB, the consistent shift in neoantigen composition suggests that it acts as an evolutionary force in resistance to response during immunotherapy.

Humanized Mouse Models for the Advancement of Innate Lymphoid Cell-Based Cancer Immunotherapies

Innate lymphoid cells (ILCs) are a branch of the immune system that consists of diverse circulating and tissue-resident cells, which carry out functions including homeostasis and antitumor immunity. The development and behavior of human natural killer (NK) cells and other ILCs in the context of cancer is still incompletely understood. Since NK cells and Group 1 and 2 ILCs are known to be important for mediating antitumor immune responses, a clearer understanding of these processes is critical for improving cancer treatments and understanding tumor immunology as a whole. Unfortunately, there are some major differences in ILC differentiation and effector function pathways between humans and mice. To this end, mice bearing patient-derived xenografts or human cell line-derived tumors alongside human genes or human immune cells represent an excellent tool for studying these pathways in vivo. Recent advancements in humanized mice enable unparalleled insights into complex tumor-ILC interactions. In this review, we discuss ILC behavior in the context of cancer, the humanized mouse models that are most commonly employed in cancer research and their optimization for studying ILCs, current approaches to manipulating human ILCs for antitumor activity, and the relative utility of various mouse models for the development and assessment of these ILC-related immunotherapies.

Abstract PR007: Lymph node colonization promotes distant tumor metastasis through the induction of systemic tumor-specific immunosuppression

The majority of cancer-associated deaths result from distant organ metastasis rather than the primary tumor, yet the mechanisms that enable this process remain poorly understood. For most solid tumors, colonization of regional or distant lymph nodes (LNs) typically precedes the formation of distant organ metastases, yet it remains unclear whether LN metastasis plays a functional role in disease progression. LNs are education hubs of the adaptive immune system wherein antigens derived from pathogens or malignancies are presented to lymphocytes to elicit an adaptive immune response. Nonetheless, LN metastasis, which is typically attributed to passive drainage of tumor cells through lymphatics, frequently does not lead to the generation of anti-tumor immunity, but instead correlates with further disease progression. Here, we find that LN metastasis represents a critical step in tumor progression through the capacity of such metastases to induce tumor-specific immunosuppression in a manner that promotes further dissemination of tumors to distant organs. Using an in vivo passaging approach of a non-metastatic syngeneic melanoma, we generated 300 unique cell lines exhibiting varying degrees of LN metastatic capacity. We show that the presence of these LN metastases enables distant organ seeding of metastases in a manner that the parental tumor cannot, and this effect is eliminated in mice lacking an adaptive immune response. Furthermore, this promotion of distant seeding by LN metastases is tumor specific. Using flow cytometry and single-cell sequencing to perform organism-wide immune profiling, we identify multiple cellular mediators of tolerance. In particular, we find that LN metastases have the capacity to both resist NK cell cytotoxicity and induce regulatory T cells (Tregs) in vitro. Furthermore, depletion of NK cells in vivo enables non-metastatic tumors to disseminate to LNs, and ablation of Tregs using FoxP3-DTR mice eliminates the occurrence of lymphatic metastases. The immunosuppressive effects of LN metastases can be transferred to tumor-naïve recipients through specific lymphocyte populations in a manner that promotes distant seeding. Through the use of whole exome sequencing, we show that neither the metastatic proclivity nor immunosuppression evolve through the acquisition of driver mutations, loss of neoantigens, loss of MHC class I presentation, or decreases in melanoma antigen expression. Rather, by RNA-seq and ATAC-seq, we show that a conserved interferon signaling axis is upregulated in LN metastases and is rendered stable through epigenetic regulation of chromatin accessibility. Furthermore, using CRISPR/Cas9, we find that these pathways are required for LN metastatic seeding, and validate their conserved significance in additional mouse models of pancreatic ductal adenocarcinoma and head and neck squamous cell carcinoma (HNSCC), along with RNA-seq analysis of malignant populations sorted from HNSCC patients. Together, these findings demonstrate a critical role for LN metastasis in promoting tumor-specific immunosuppression.

Citation Format: Nathan E. Reticker-Flynn, Weiruo Zhang, Serena Chang, Andrew J. Gentles, John B. Sunwoo, Christina S. Kong, Sylvia K. Plevritis, Edgar G. Engleman. Lymph node colonization promotes distant tumor metastasis through the induction of systemic tumor-specific immunosuppression [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr PR007.

AHR Regulates NK Cell Migration via ASB2-Mediated Ubiquitination of Filamin A

Natural killer (NK) cells are effector cells of the innate immune system involved in defense against virus-infected and transformed cells. The effector function of NK cells is linked to their ability to migrate to sites of inflammation or damage. Therefore, understanding the factors regulating NK cell migration is of substantial interest. Here, we show that in the absence of aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, NK cells have reduced capacity to migrate and infiltrate tumors in vivo. Analysis of differentially expressed genes revealed that ankyrin repeat and SOCS Box containing 2 (Asb2) expression was dramatically decreased in Ahr-/- NK cells and that AhR ligands modulated its expression. Further, AhR directly regulated the promoter region of the Asb2 gene. Similar to what was observed with murine Ahr-/- NK cells, ASB2 knockdown inhibited the migration of human NK cells. Activation of AHR by its agonist FICZ induced ASB2-dependent filamin A degradation in NK cells; conversely, knockdown of endogenous ASB2 inhibited filamin A degradation. Reduction of filamin A increased the migration of primary NK cells and restored the invasion capacity of AHR-deficient NK cells. Our study introduces AHR as a new regulator of NK cell migration, through an AHR-ASB2-filamin A axis and provides insight into a potential therapeutic target for NK cell-based immunotherapies.

Defining best practices for tissue procurement in immuno-oncology clinical trials: consensus statement from the Society for Immunotherapy of Cancer Surgery Committee

Immunotherapy is now a cornerstone for cancer treatment, and much attention has been placed on the identification of prognostic and predictive biomarkers. The success of biomarker development is dependent on accurate and timely collection of biospecimens and high-quality processing, storage and shipping. Tumors are also increasingly used as source material for the generation of therapeutic T cells. There have been few guidelines or consensus statements on how to optimally collect and manage biospecimens and source material being used for immunotherapy and related research. The Society for Immunotherapy of Cancer Surgery Committee has brought together surgical experts from multiple subspecialty disciplines to identify best practices and to provide consensus on how best to access and manage specific tissues for immuno-oncology treatments and clinical investigation. In addition, the committee recommends early integration of surgeons and other interventional physicians with expertise in biospecimen collection, especially in clinical trials, to optimize the quality of tissue and the validity of correlative clinical studies in cancer immunotherapy.

Association Between Immunosuppression and Outcomes in Oral Cavity Squamous Cell Carcinoma

OBJECTIVE

To assess the effect of immunosuppression on recurrence and mortality outcomes in oral cavity squamous cell carcinoma (SCC) after initial surgical treatment.

STUDY DESIGN

Retrospective cohort study.

SETTING

A single academic tertiary referral center.

METHODS

Patients with oral cavity SCC treated with initial surgery were included. Immunosuppressed versus nonimmunosuppressed groups were compared. Primary end points were 5-year overall recurrence and all-cause mortality. Secondary end points were recurrence subtypes (local, regional, and distant) and disease-specific mortality.

RESULTS

Of 803 patients with oral cavity SCC, 71 (9%) were immunosuppressed from therapeutic drug use (n = 48) or systemic disease (n = 23). The immunosuppressed group consisted of patients with a history of transplant (21%), autoimmune or pulmonary disorder (45%), hematologic malignancy or myeloproliferative disorder (30%), and HIV infection (3%). After adjusting for baseline variables of age, sex, comorbidities, pathologic tumor characteristics, and adjuvant treatment, all recurrence and mortality outcomes were worse in the immunosuppressed group. The multivariate-adjusted hazard ratio for overall recurrence was 2.16 (95% CI, 1.50-3.12; P < .01), and all-cause mortality was 1.79 (95% CI, 1.15-2.78; P < .01) in Cox regression analysis. The 2 groups were then matched in a 1:5 ratio according to the same baseline variables. All end points apart from disease-specific mortality were significantly worse in the immunosuppressed group after matching.

CONCLUSION

This study demonstrates that immunosuppression is associated with poor outcomes in oral cavity SCC, with an approximate 2-fold increase in rates of recurrence and mortality. Future studies are needed to assess the risks and benefits of adjusting therapeutic immunosuppression in this population.

Malignant cell-specific CXCL14 promotes tumor lymphocyte infiltration in oral cavity squamous cell carcinoma

Objectives

To explore lymphocyte infiltration as a potential mechanism behind CXCL14-mediated tumor growth suppression in oral cavity squamous cell carcinoma (OSCC).

Methods

We analyzed single cell RNA-sequencing (scRNA-seq) data from OSCC to identify expression changes among malignant cells in lymph nodes (LN) versus primary tumors. CXCL14 expression in murine OSCC cell lines was quantified using qRT-PCR. Short hairpin RNA knockdown of CXCL14 was performed in mouse oral cavity (MOC)1 cells, and CXCL14 overexpression was performed in MOC2 cells. Cells in each condition were injected into C57BL/6 mice with and without T cell depletion, and tumor volume was measured. At 30 days, tumors were dissociated and analyzed by flow cytometry for CD45⁺CD3⁺ T cells. CXCL14 expression was correlated with gene expression signatures of tumor infiltrating lymphocytes (TIL) in scRNA-seq data, as well as TCGA tumors.

Results

scRNA-seq revealed CXCL14 as the most significantly downregulated gene among malignant cells in LNs relative to primary tumor, supporting a role in preventing invasion and/or metastasis. In a murine immunocompetent model, CXCL14 expression was higher in indolent MOC1 cells than in more aggressive MOC2 cells. Tumor growth in vivo was significantly increased by CXCL14 knockdown in MOC1 cells relative to control, with a corresponding decrease in TIL. In MOC2 cells, tumor growth was significantly reduced by CXCL14 overexpression relative to control and TIL were increased. Both effects were lost with T cell depletion. In a human tumor scRNA-seq cohort, we found that only malignant cell CXCL14, but not non-malignant cell or fibroblast CXCL14, was associated with TIL. Bulk CXCL14 from the TCGA cohort had no association with TIL.

Conclusions

Higher CXCL14 expression by tumor cells is associated with reduced tumor growth and increased TIL, supporting immune-mediated suppression of tumor growth in OSCC. Given that CXCL14 is downregulated in LN metastases compared with primary tumors, our data raise the possibility that CXCL14-mediated immune infiltration may discourage invasion and metastasis. In human scRNA-seq data, only malignant cell-specific CXCL14 was associated with TIL, suggesting a critical context-dependent effect of CXCL14 expression.

Abstract 3419: Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immunosuppression

The majority of cancer-associated deaths result from distant organ metastasis rather than the primary tumor, yet the mechanisms that enable this process remain poorly understood. For most solid tumors, colonization of regional or distant lymph nodes (LNs) typically precedes the formation of distant organ metastases, yet it remains unclear whether LN metastasis plays a functional role in disease progression. LNs are education hubs of the adaptive immune system wherein antigens derived from pathogens or malignancies are presented to lymphocytes to elicit an adaptive immune response. Nonetheless, LN metastasis, which is typically attributed to passive drainage of tumor cells through lymphatics, frequently does not lead to the generation of anti-tumor immunity, but instead correlates with further disease progression. Here, we find that LN metastasis represents a critical step in tumor progression through the capacity of such metastases to induce tumor-specific immunosuppression in a manner that promotes further dissemination of tumors to distant organs. Using an in vivo passaging approach of a non-metastatic syngeneic melanoma, we generated 300 unique cell lines exhibiting varying degrees of LN metastatic capacity. Transcriptional profiling of the lines reveals a conserved enrichment for immune-related programs. We show that the presence of these LN metastases enables distant organ seeding of metastases in a manner that the parental tumor cannot, and this differential seeding is eliminated in mice lacking an adaptive immune response. Furthermore, this promotion of distant seeding by LN metastases is tumor specific. Using mass cytometry to perform organism-wide immune profiling, we identify multiple cellular mediators of tolerance. In particular, we find that LN metastases have the capacity to both resist NK cell cytotoxicity and induce regulatory T cells (Tregs) in vitro. Furthermore, depletion of NK cells in vivo enables non-metastatic tumors to disseminate to LNs, and ablation of Tregs using FoxP3-DTR mice eliminates the occurrence of lymphatic metastases. Through the use of whole exome sequencing, we show that neither the metastatic proclivity nor immunosuppression evolve through the acquisition of driver mutations, loss of neoantigens, loss of MHC class I presentation, or decreases in melanoma antigen expression. Rather, by RNA-seq and ATAC-seq, we show that a conserved interferon signaling axis is upregulated in LN metastases and is rendered stable through epigenetic regulation of chromatin accessibility. Furthermore, using CRISPR/Cas9, we find that these pathways are required for LN metastatic seeding, and validate their conserved significance in additional mouse models of pancreatic ductal adenocarcinoma and head and neck squamous cell carcinoma (HNSCC), along with RNA-seq analysis of malignant populations sorted from HNSCC patients. Together, these findings demonstrate a critical role for LN metastasis in promoting tumor-specific immunosuppression.

Citation Format: Nathan E. Reticker-Flynn, Pamela A. Basto, Weiruo Zhang, Maria M. Martins, Serena Chang, Andrew J. Gentles, John B. Sunwoo, Sylvia K. Plevritis, Edgar G. Engleman. Lymph node colonization promotes distant tumor metastasis through the induction of tumor-specific immunosuppression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3419.

Application of salivary noncoding microRNAs for the diagnosis of oral cancers

Oral cancer is on the rise globally and survival rates, despite improvements in clinical care, have not significantly improved. Early detection followed by immediate intervention is key to improving patient outcomes. The use of biomarkers has changed the diagnostic landscape for many cancers. For oral cancers, visual inspection followed by a tissue biopsy is standard practice. The discovery of microRNAs as potential biomarkers has attracted clinical interest but several challenges remain. These microRNAs can be found in bodily fluids such as blood and saliva which have been investigated as potential sources of biomarker discovery. As oral cancer is localized within the oral cavity, saliva may contain clinically relevant molecular markers for disease detection. Our review provides an outline of the current advances for the application of salivary microRNAs in oral cancer. We also provide a technical guide for the processing of salivary RNAs to ensure accurate clinical measurement and validation.

Exome scale liquid biopsy characterization of putative neoantigens and genomic biomarkers pre- and post anti-PD-1 therapy in squamous cell carcinoma of the head and neck

6557

Background: The reduced scope, and number of genes profiled by typical liquid biopsy panels can result in missed biomarkers including neoantigens, which may change with treatment, as well as potentially undetected resistance mechanisms and pathways beyond the scope of targets typically captured by panels. To address these limitations, we used a whole-exome scale liquid biopsy monitoring platform, NeXT Liquid Biopsy, to analyze head and neck squamous cell carcinoma (HNSCC) patients that have received anti-PD1 therapy. Presently, we sought to (1) monitor neoantigen changes in cfDNA as a complement to tumor biopsy-derived neoantigens, (2) compare the impact of tumor escape mechanisms, including HLA-LOH, on neoantigens identified in tissue and cfDNA and (3) to identify novel biological signatures that combine information from both solid tumor and liquid biopsies. Methods: Pre- and post-intervention matched normal, tumor and plasma samples were collected from a cohort of 12 patients with HNSCC. Following baseline sample collection all patients received a single dose of nivolumab, followed by resection approximately one month later when feasible, or a second biopsy where resection was impractical. Solid tumor and matched normal samples were profiled using ImmunoID NeXT, an augmented exome/transcriptome platform and analysis pipeline. Exome-scale somatic variants were identified in cfDNA from plasma samples using the NeXT Liquid Biopsy platform. Data from these two platforms were compared with corresponding clinical findings. Results: Concordant somatic events were detected between plasma and tumor at pre- and post-treatment timepoints. Neoantigens predicted to arise from these somatic events were reduced in solid tumor post-treatment, but increased in cfDNA, when compared to pre-treatment timepoints. HLA LOH was identified in a number of subjects, likely resulting in reduced neoepitope presentation in those cases. Immune cell infiltration increased in the tumor following treatment, with no changes to the CD8+/Treg cell ratio, suggesting consistent immunoregulation. Conclusions: Exome-wide neoantigen burden was reliably predicted from cfDNA, providing additional insight complementing data from solid tumor. Analyzing HLA LOH, and neoantigen burden from both solid and liquid biopsies together over the course of treatment creates a more comprehensive profile of therapeutic response and resistance mechanisms in HNSCC patients missed with typical liquid biopsy panels.

Framework for prioritizing head and neck surgery during the COVID-19 pandemic

The COVID‐19 pandemic has placed an extraordinary demand on the United States health care system. Many institutions have canceled elective and non‐urgent procedures to conserve resources and limit exposure. While operational definitions of elective and urgent categories exist, there is a degree of surgeon judgment in designation. In the present commentary, we provide a framework for prioritizing head and neck surgery during the pandemic. Unique considerations for the head and neck patient are examined including risk to the oncology patient, outcomes following delay in head and neck cancer therapy, and risk of transmission during otolaryngologic surgery. Our case prioritization criteria consist of four categories: urgent—proceed with surgery, less urgent—consider postpone > 30 days, less urgent—consider postpone 30 to 90 days, and case‐by‐case basis. Finally, we discuss our preoperative clinical pathway for transmission mitigation including defining low‐risk and high‐risk surgery for transmission and role of preoperative COVID‐19 testing.

Plasticity and Polarization of Human NK Cells in the Tumor Microenvironment

The presence and function of innate lymphoid cells (ILC), including natural killer (NK) cells, within human tumors has been poorly characterized. Here, we have assessed the heterogeneity of NK and ILC populations by single-cell RNA sequencing (scRNAseq) of hundreds of individual NK cells and ILCs within human head and neck squamous cell carcinoma (HNSCC), matched lymph node metastases, matched peripheral blood, and blood from healthy donors. Fresh tumor specimens and blood were obtained from 8 patients undergoing surgical resection of HNSCC. Unsupervised clustering revealed 8 different clusters of NK cells and ILC subsets. We observed significant heterogeneity, with distinct subsets showing profiles consistent with that of conventional NK cells, ILC1-like cells and ILC3-like cell. Importantly, peripheral NK cells were distinct from intratumoral NK cells. The presence of these different cell subsets within primary HNSCC tumors was confirmed by flow cytometry. Further, plasticity between the NK cell subsets was supported by in vitro and in vivo experimental data. Given the ability of NK and ILCs to polarize the immune responses through the secretion of cytokines and the ability of certain subsets to kill target cells, we hypothesize that the differences observed in NK and ILC populations and their plasticity may result in different immune responses, and may influence clinical outcomes following therapy.

Managing head and neck cancer patients with tracheostomy or laryngectomy during the COVID-19 pandemic

Head and neck cancer patients with tracheostomies and laryngectomies, as well as their healthcare providers, face unique challenges in the context of the current COVID-19 pandemic. This document consolidates best available evidence to date and presents recommendations to minimize the risks of aerosolization and SARS-CoV-2 exposures in both the inpatient and outpatient settings. The cornerstones of these recommendations include the use of closed-circuit ventilation whenever possible, cuffed tracheostomy tubes, judicious use of heat moisture exchange units, appropriate personal protective equipment for providers and patients, meticulous hand hygiene, and minimal manipulation of tracheostomy tubes.

Abstract B28: ERAP2 overexpression is a marker for reduced anti-PD-1 response in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an EBV-associated epithelial cancer common in the Southern Chinese population. Patients with recurrent or metastatic NPC treated with PD-1 blockade showed a response rate of 20.5%, with no correlation observed between the expression of PD-L1 and treatment response. In an effort to identify biomarkers for anti-PD-1 treatment response, we evaluated a cohort of 10 NPC patients with recurrent or metastatic NPC treated with nivolumab or pembrolizumab. Laser capture microdissection was performed on pretreatment biopsies, with tumor and microenvironment compartments separately microdissected. Nasopharyngeal epithelium from normal nasopharyngeal biopsies were also microdissected as controls. Smart-3SEQ, a novel 3´ end RNA-Seq technique that allows for the accurate quantification of transcript abundance in FFPE samples, was performed to obtain gene expression libraries. ERAP2, a zinc metalloaminopeptidase that performs N-terminal trimming of antigenic epitopes for presentation by MHC class I, was among the most highly upregulated genes in the tumor compartment of nonresponders (adjusted p = 0.033). ERAP2 overexpression was also observed in NPC tumors compared to normal controls. Immunohistochemistry validated the overexpression of ERAP2 in nonresponders, while responders had similar expression to normal controls. In conclusion, ERAP2 is overexpressed in NPC tumors and is a promising biomarker for reduced anti-PD-1 response in NPC.

Citation Format: Joshua K. Tay, Brigette B.Y. Ma, Sushama Varma, Yaw Chyn Lim, Chee Seng Tan, Kwok Wai Lo, John B. Sunwoo, Kevin J. Cullen, Boon Cher Goh, Robert B. West. ERAP2 overexpression is a marker for reduced anti-PD-1 response in nasopharyngeal carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr B28.

Abstract 2703: Lymph node colonization promotes distant tumor metastasis through the induction of systemic immune tolerance

The majority of cancer-associated deaths are the result of distant organ metastasis, an event that is typically preceded by metastasis to regional or distant lymph nodes (LNs). LNs are education hubs of the adaptive immune system wherein antigens derived from pathogens or malignancies are presented to lymphocytes in a manner that facilitates elimination of the threat. Nonetheless, LN metastasis, which is typically attributed to passive drainage of tumor cells through lymphatics, frequently does not lead to the generation of an anti-tumor immune response, but instead correlates with poor prognosis and further disease progression. Here, we find that LN metastasis represents a critical step in tumor progression through the capacity of such metastases to induce systemic immune tolerance in a manner that promotes further dissemination of tumors to distant organs. Through serial in vivo passaging of a syngeneic melanoma in mice, we generate nearly 300 unique cell lines that exhibit an enhanced capacity to metastasize to LNs. Transcriptional profiling of these lines reveals increased expression of immune-related programs. We show that the presence of these LN metastases enables distant organ seeding of metastases in a manner that the parental tumor cannot, and this differential seeding is eliminated in mice that lack an adaptive immune response. To query the effects of the LN metastases on the systemic immune response, we perform organism-wide immune profiling by mass cytometry and identify a number of cellular mediators of tolerance. In particular, we find that LN metastases have the capacity to both resist NK cell cytotoxicity and induce regulatory T cells (Tregs) in vitro. Furthermore, depletion of NK cells in vivo enables non-metastatic tumors to disseminate to LNs, and ablation of Tregs using FoxP3-DTR mice eliminates the occurrence of lymphatic metastases. We further identify an interferon signaling axis that is constitutively activated within the LN metastases in the absence of exogenous interferon signaling. Through the use of ATAC-seq, we find that this program is conferred through epigenetic regulation of chromatin accessibility. Knockout of key interferon-induced genes using CRISPR/Cas9 in the LN-metastatic cells reveals that this program is required for enhanced LN metastatic seeding in vivo, and their overexpression increases LN metastasis of the non-metastatic cells. Using additional mouse models of pancreatic ductal adenocarcinoma and head and neck squamous cell carcinoma (HNSCC), we show that these findings are conserved across multiple malignancies. Additionally, we perform RNA-seq on sorted malignant populations from node-positive and node-negative HNSCC patients and confirm that these differences in transcriptional profiles extend to the human disease. Together, these findings demonstrate a critical role for LN metastasis in promoting tumor immune tolerance.

Citation Format: Nathan E. Reticker-Flynn, Maria M. Martins, Pamela A. Basto, Weiruo Zhang, Alborz Bejnood, Andrew J. Gentles, John B. Sunwoo, Sylvia K. Plevritis, Edgar G. Engleman. Lymph node colonization promotes distant tumor metastasis through the induction of systemic immune tolerance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2703.

Natural Killer Cells and Thyroid Diseases

Abnormal production of thyroid hormone is one of the common endocrine disorders, and thyroid hormone production declines with age. The aging process also negatively affects the immune system. An interaction between endocrine system and the immune system has been proposed to be bidirectional. Emerging evidence suggests an interaction between a lymphocyte population, called natural killer (NK) cells and thyroid gland function. Here, we review the relationship between NK cells and thyroid function and disease.

The Immune Subtypes and Landscape of Squamous Cell Carcinoma

PURPOSE

To identify immune subtypes and investigate the immune landscape of squamous cell carcinomas (SCC), which share common etiology and histologic features.

EXPERIMENTAL DESIGN

Based on the immune gene expression profiles of 1,368 patients with SCC in the Cancer Genome Atlas (TCGA), we used consensus clustering to identify robust clusters of patients and assessed their reproducibility in an independent pan-SCC cohort of 938 patients. We further applied graph structure learning-based dimensionality reduction to the immune profiles to visualize the distribution of individual patients.

RESULTS

We identified and independently validated six reproducible immune subtypes associated with distinct molecular characteristics and clinical outcomes. An immune-cold subtype had the least amount of lymphocyte infiltration and a high level of aneuploidy, and these patients had the worst prognosis. By contrast, an immune-hot subtype demonstrated the highest infiltration of CD8⁺ T cells, activated NK cells, and elevated IFNγ response. Accordingly, these patients had the best prognosis. A third subtype was dominated by M2-polarized macrophages with potent immune-suppressive factors such as TGFβ signaling and reactive stroma, and these patients had relatively inferior prognosis. Other subtypes showed more diverse immunologic features with intermediate prognoses. Finally, our analysis revealed a complex immune landscape consisting of both discrete clusters and continuous spectrum.

CONCLUSIONS

This study provides a conceptual framework to understand the tumor immune microenvironment of SCCs. Future work is needed to evaluate its relevance in the design of combination treatment strategies and guiding optimal selection of patients for immunotherapy.

Implementation of a targeted HPV educational program in a population with HIV

Patients living with human immunodeficiency virus (PLWH) are at higher risk of developing human papillomavirus (HPV)-associated malignancies. This prospective, longitudinal study evaluated the baseline knowledge of PLWH regarding HPV infection and its association with head neck cancer, and it aimed to determine whether a focused educational session could promote both short- and long-term knowledge acquisition in this population. Twenty-seven subjects participated in an interactive educational session and completed pre-test and immediate and delayed (4-month) post-test questionnaires. When compared to their pre-test answers, subjects demonstrated significant improvements in all 28 questions immediately following education. Knowledge preservation was demonstrated 4 months after initial evaluation, with subjects performing significantly better than their pre-test scores in 24 of the original 28 questions. These results suggest that short, focused, educational programs for PLWH may promote a better understanding of HPV's association with human immunodeficiency virus (HIV) and HPV risk factors, methods of transmission, and prevention.

Organoid Modeling of the Tumor Immune Microenvironment

In vitro cancer cultures, including three-dimensional organoids, typically contain exclusively neoplastic epithelium but require artificial reconstitution to recapitulate the tumor microenvironment (TME). The co-culture of primary tumor epithelia with endogenous, syngeneic tumor-infiltrating lymphocytes (TILs) as a cohesive unit has been particularly elusive. Here, an air-liquid interface (ALI) method propagated patient-derived organoids (PDOs) from >100 human biopsies or mouse tumors in syngeneic immunocompetent hosts as tumor epithelia with native embedded immune cells (T, B, NK, macrophages). Robust droplet-based, single-cell simultaneous determination of gene expression and immune repertoire indicated that PDO TILs accurately preserved the original tumor T cell receptor (TCR) spectrum. Crucially, human and murine PDOs successfully modeled immune checkpoint blockade (ICB) with anti-PD-1- and/or anti-PD-L1 expanding and activating tumor antigen-specific TILs and eliciting tumor cytotoxicity. Organoid-based propagation of primary tumor epithelium en bloc with endogenous immune stroma should enable immuno-oncology investigations within the TME and facilitate personalized immunotherapy testing.

PD-L1 Expression and Tumor-Infiltrating Lymphocytes in High-Risk and Metastatic Cutaneous Squamous Cell Carcinoma

OBJECTIVE

To characterize programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) positivity for locally aggressive or regionally metastatic cutaneous head and neck squamous cell carcinoma (cHNSCC).

STUDY DESIGN

Retrospective chart review, followed by immunohistochemical staining of archived tumor specimens.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

After identification of 101 patients treated surgically for locally advanced or regionally metastatic cHNSCC, archived tissue was stained and graded for PD-L1 expression in addition to TIL presence. Cross-tabulation was performed to examine the association between either of these variables and clinicopathologic features and outcomes.

RESULTS

A total of 101 patients met inclusion criteria, but archived tissue was available only for 83 (31 primaries, 52 metastases). The majority of primary tumors demonstrated grade 1 PD-L1 staining, while grade 2 staining was more likely for metastases. Neither high- nor low-grade PD-L1 expression correlated with any clinicopathologic variable for primary tumors. However, for metastases, high-grade staining was significantly associated with regional recurrence (15 of 19, P = .02). TILs were present for 65% of primary tumors and 90% of regional metastases but did not correlate with any clinicopathologic variables.

CONCLUSION

Diffuse expression of PD-L1 in this study highlights the possibility of using immunotherapy in the form of programmed death 1/PD-L1 blockade to improve treatment for this devastating disease. However, further studies are needed to clarify the significance of PD-L1 expression and TIL positivity for locally advanced or regionally metastatic cHNSCC.

American Thyroid Association Statement on Postoperative Hypoparathyroidism: Diagnosis, Prevention, and Management in Adults

BACKGROUND

Hypoparathyroidism (hypoPT) is the most common complication following bilateral thyroid operations. Thyroid surgeons must employ strategies for minimizing and preventing post-thyroidectomy hypoPT. The objective of this American Thyroid Association Surgical Affairs Committee Statement is to provide an overview of its diagnosis, prevention, and treatment.

SUMMARY

HypoPT occurs when a low intact parathyroid hormone (PTH) level is accompanied by hypocalcemia. Risk factors for post-thyroidectomy hypoPT include bilateral thyroid operations, autoimmune thyroid disease, central neck dissection, substernal goiter, surgeon inexperience, and malabsorptive conditions. Medical and surgical strategies to minimize perioperative hypoPT include optimizing vitamin D levels, preserving parathyroid blood supply, and autotransplanting ischemic parathyroid glands. Measurement of intraoperative or early postoperative intact PTH levels following thyroidectomy can help guide patient management. In general, a postoperative PTH level <15 pg/mL indicates increased risk for acute hypoPT. Effective management of mild to moderate potential or actual postoperative hypoPT can be achieved by administering either empiric/prophylactic oral calcium and vitamin D, selective oral calcium, and vitamin D based on rapid postoperative PTH level(s), or serial serum calcium levels as a guide. Monitoring for rebound hypercalcemia is necessary to avoid metabolic and renal complications. For more severe hypocalcemia, inpatient management may be necessary. Permanent hypoPT has long-term consequences for both objective and subjective well-being, and should be prevented whenever possible.

Abstract 4684: NSD1 inactivation defines an immune cold, DNA hypomethylated subtype in squamous cell carcinoma

Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Chromatin modifying enzymes are frequently mutated in cancer, resulting in widespread epigenetic deregulation. Recent reports indicate that inactivating mutations in the histone methyltransferase NSD1 define an intrinsic subtype of head and neck squamous cell carcinoma (HNSC) that features pronounced DNA hypomethylation. We have identified a similar hypomethylated subtype of lung squamous cell carcinoma (LUSC) that is enriched for both inactivating mutations and deletions in NSD1. We identified cancer DNA methylation subtypes by first applying the MethylMix algorithm to whole genome DNA methylation and gene expression data from The Cancer Genome Atlas to identify DNA methylation deregulated genes, followed by consensus clustering to patients based on their profiles of these deregulated genes. The ‘NSD1 subtypes' of HNSC and LUSC are highly correlated at the DNA methylation and gene expression levels, featuring ectopic expression of developmental transcription factors and genes that are also hypomethylated in Sotos syndrome, a congenital disorder caused by germline NSD1 mutations. Further, the NSD1 subtype of HNSC displays an ‘immune cold' phenotype characterized by low infiltration of tumor-associated leukocytes, particularly pro-inflammatory M1 macrophages and CD8+ T cells, as well as low expression of genes encoding the immunotherapy target PD-1 immune checkpoint receptor and its ligands. Using an in vivo model, we demonstrate that NSD1 inactivation results in reduced T cell infiltration into the tumor microenvironment, implicating NSD1 as a tumor cell-intrinsic driver of an immune cold phenotype. NSD1 inactivation therefore drives widespread oncogene expression across cancer sites, and has implications for immunotherapy. &lt;!–EndFragment–&gt;

Citation Format: Kevin Brennan, Olivier Gevaert, John B. Sunwoo, June Ho Shin. NSD1 inactivation defines an immune cold, DNA hypomethylated subtype in squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4684.

ESM1 mediates NGFR-induced invasion and metastasis in murine oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a highly invasive and metastatic malignancy. The nerve growth factor receptor (NGFR) has been observed to be expressed on a subset of cells in OSCC, and NGFR⁺ cells have greater tumor-initiating capacity in vivo. Further, inhibition of NGFR reduces tumor growth, indicating a functional role of this receptor; however, the mechanisms by which NGFR confers enhanced tumor formation are not known. Here, we used an established murine model of OSCC and gene expression array analysis to identify ESM1 as a downstream target gene of NGFR, critical for tumor invasion and metastasis. ESM1 encodes a protein called endocan, which has the property of regulating proliferation, differentiation, migration, and adhesion of different cell types. Incubation of NGFR⁺ murine OSCC cells with nerve growth factor resulted in increased expression of ESM1. Importantly, ESM1 overexpression conferred an enhanced migratory, invasive, and metastatic phenotype, similar to what has been correlated with NGFR expression. Conversely, shRNA knockdown of ESM1 in NGFR overexpressing OSCC cells abrogated the tumor growth kinetics and the invasive and metastatic properties associated with NGFR. Together, our data indicate that NGFR plays an important role in the pathogenesis and progression of OSCC via regulation of ESM1.