Overexpression of PD-L2 is associated with shorter relapse-free survival in patients with malignant salivary gland tumors

The tumor microenvironment of benign and malignant salivary gland tumors

BACKGROUND

Treatment of salivary gland tumors (SGTs) remains challenging. Little is known about the immune landscape of SGTs. We aimed to characterize the tumor microenvironment in benign and malignant SGTs.

METHODS

Eleven benign and nine malignant tumors were collected from patients undergoing curative intent surgery. Specimens were analyzed using mass cytometry by time-of-flight. Immune cell populations were manually gated, and T cells were clustered using the FlowSOM algorithm. Population frequencies were compared between high-grade and low-grade malignancies, corrected for multiple hypothesis testing.

RESULTS

There were trends towards increased CD4+ and CD8+ T cells among malignant tumors. High-grade malignancies exhibited trends towards higher frequencies of CD8+ PD-1+ CD39+ CD103+ exhausted T cells, CD4+ FoxP3+ TCF-1+ CD127- Tregs, and CD69+ CD25- CD4+ T cells compared to low-grade malignancies.

CONCLUSION

SGTs exhibit significant immunologic diversity. High-grade malignancies tended to have greater infiltration of exhausted CD8+ T cells and Tregs, which may guide future studies for immunotherapy strategies.

PD-L1 and PD-L2 Expression in Different Tumor Stages and Types of Malignant Salivary Gland Neoplasms: A Single-center Experience

There is a limited amount of data on the role of programmed cell death ligand (PD-L) -1 and PD-L2 in salivary gland carcinomas. We aimed to evaluate the prognostic value of PD-L1 and PD-L2 expressions, which are closely related to immune mechanisms, with respect to salivary gland tumor types and stages. Data from patients with salivary gland masses surgically removed between 2006 and 2021, diagnosed with a malignant salivary gland neoplasm, were retrospectively analyzed. Immunoreactivity for PD-L1 and PD-L2 was performed on resection materials. The mean age of 90 patients was 52.1±18.8 and 46.7% were male. Overall, 55.6% of patients were diagnosed with adenoid cystic carcinoma (ACC), 23.3% with mucoepidermoid carcinoma (MEC), 16.7% with acinic cell carcinoma (AciCC), 3.3% with ductal carcinoma (DC), and 1 patient with pleomorphic adenoma ex carcinoma (PA-ex-CA). In all, 52% of ACC, 12% of AciCC, 24% of MEC, and 12% of DC cases were at stage IV. The tumor diameter, frequencies of lymphovascular invasion, metastasis, positive surgical margin, recurrence, and mortality rates of patients at stages III and IV were significantly larger than those at stages I and II ( P <0.05). The percentages of tumor cell score (TCS) and immune cell score (ICS) for PD-L1 were significantly higher among patients with MEC compared with those with other types of tumors ( P =0.0011). However, the percentages of combined score (CS) for PD-L1 and tumor cell score for PD-L2 were comparable among tumor types ( P >0.05). No significant difference was found in these scores for PD-L1 between tumor stages ( P >0.05), but for PD-L2, all patients at stage I had TCS <1% for PD-L2, while all patients at stages II and III, and 92% of patients at stage IV had TCS ≥1% ( P <0.0001). High expression of PD-L1 was mostly observed in MEC cases ( P =0.0016), while all patients with AciCC had a low PD-L1 expression level ( P =0.0206). The mean tumor diameter, rate of lymphovascular invasion, perineural invasion, metastasis, positive surgical margin, recurrence, type of treatment, mortality, and TILs ratio did not differ significantly according to PD-L1 expression level ( P >0.05). The percentage of tumor-infiltrating lymphocytes was comparable among negative and positive PD-L1 scores according to both 1% and 5% threshold values ( P >0.05). High PD-L1 expression is rare in AciCC, while PD-L1 expression is high in MEC. Our findings underline the importance of future screening for PD-L1 and PD-L2 before patients undergoing immunotherapies in all salivary gland tumors.

Artificial intelligence-powered spatial analysis of tumor-infiltrating lymphocytes as a predictive biomarker for axitinib in adenoid cystic carcinoma

BACKGROUND

This study analyzed the predictive value of artificial intelligence (AI)-powered tumor-infiltrating lymphocyte (TIL) analysis in recurrent or metastatic (R/M) adenoid cystic carcinoma (ACC) treated with axitinib.

METHODS

Patients from a multicenter, prospective phase II trial evaluating axitinib efficacy in R/M ACC were included in this study. H&E whole-side images of archival tumor tissues were analyzed by Lunit SCOPE IO, an AI-powered spatial TIL analyzer.

RESULTS

Twenty-seven patients were included in the analysis. The best response was stable disease, and the median progression-free survival (PFS) was 11.1 months (95% CI, 9.2-13.7 months). Median TIL densities in the cancer and surrounding stroma were 25.8/mm2 (IQR, 8.3-73.0) and 180.4/mm2 (IQR, 69.6-342.8), respectively. Patients with stromal TIL density >342.5/mm2 exhibited longer PFS (p = 0.012).

CONCLUSIONS

Cancer and stromal area TIL infiltration were generally low in R/M ACC. Higher stromal TIL infiltration was associated with a longer PFS with axitinib treatment.

Prognostic value and clinicopathological roles of the tumor immune microenvironment in salivary duct carcinoma

Salivary duct carcinoma (SDC) is an aggressive type of salivary gland carcinoma. Recently, immunotherapies targeting immune checkpoints, including PD1, PD-L1, CTLA4, and LAG3, have had a considerable prognostic impact on various malignant tumors. The implementation of such immune checkpoint inhibitor (ICI) therapies has also been attempted in cases of salivary gland carcinoma. The tumor immune microenvironment (TIME) is implicated in tumorigenesis and tumor progression and is closely associated with the response to ICI therapies. However, the TIME in SDC has not been fully explored. We examined the immunohistochemical expression of CD8, FOXP3, PD1, PD-L1, CTLA4, LAG3, and mismatch repair (MMR) proteins, tumor-infiltrating lymphocytes (TILs), and microsatellite instability (MSI) status in 175 cases of SDC. The associations between these TIME-related markers and the clinicopathological factors and prognosis were evaluated. An elevated expression of CD8, FOXP3, PD1, CTLA4, and LAG3 was associated with more aggressive histological features and an advanced N and/or M classification, elevated Ki-67 index, and poor prognosis. Furthermore, cases with a high PD-L1 expression exhibited more aggressive histological features and adverse clinical outcomes than those with a low expression. Alternatively, there was no significant correlation between TILs and clinicopathological factors. No SDC cases with an MSI-high status or MMR deficiency were found. The coexistence of both an immunostimulatory and immunosuppressive TIME in aggressive SDC might play a role in the presence of T-cell exhaustion. The contribution of multiple immune escape pathways, including regulatory T cells and immune checkpoints, may provide a rationale for ICI therapy, including combined PD1/CTLA4 blockade therapy.

Prognostic Impact of Tumor Immune Microenvironment and Its Predictive Role in Salivary Gland Cancer

BACKGROUND

Recently, many studies have investigated the role of tumor immune microenvironment (TIME) in carcinogenesis, highlighting its relation to both tumor regression and progression. In particular, the "inflammatory system", made of innate and adaptive immune cells, interacts with cancer cells and their surrounding stroma. In this setting, the aim of this review is to summarize the current literature regarding the TIME of major salivary gland carcinomas (MSGCs), with particular attention on the characteristics and prognostic role of tumor infiltrating lymphocytes (TILs), the mechanisms that lead to TILs exhaustion and the important additional immune infiltrating factors that help SGC progression or remission.

METHODS

A comprehensive literature search was performed concerning published articles on the role of TIME in MSGCs.

RESULTS

In this work we summarize the advancing knowledge on TIME in SGCs by demonstrating the key prognostic and/or predictive value of specific immune features.

CONCLUSION

From the analysis of the current 'status of the art' it clearly emerges a need for precise, unambiguous phenotyping of immune cell populations, as well as a more thorough understanding of the frequencies and interactions of multiple immune cell types inside the TIME and their spatial localization (intratumoral vs. stromal).

Simultaneous Expression of PD-1 and PD-L1 in Peripheral and Central Immune Cells and Tumor Cells in the Benign and Malignant Salivary Gland Tumors Microenvironment

BACKGROUND

To investigate the differential expression of PD-1 and PD-L1 in salivary gland tumors (SGTs, malignant and benign subtypes) and determine their association with the clinicopathological characterization of the patients.

METHODS

The immunohistochemistry was used to examine PD-1 and PD-L1 expression in specimens from 83 patients with primary SGTs including salivary ductal carcinoma (SDC), adenoid cystic carcinoma (AdCC), acinic cell carcinoma (ACC), mucoepidermoid carcinoma (MEC), warthin's tumors (WT), poleomorphic adenoma (PA) and other subtypes.

RESULTS

The expression of PD-1 in peripheral and central immune cells (ICs) of MEC, and peripheral ICs of ACC was significantly higher than those with AdCC (P = 0.02, P = 0.02, P = 0.03, respectively). Interestingly, the expression of PD-1 was also observed in peripheral and central malignant tumor cells (TCs), particularly in SDC and ACC. Despite no significant difference in PD-L1 expression of TCs among malignant subtypes, the peripheral and central ICs of ACC and MEC were revealed to express PDL-1 significantly more than those with AdCC (P < 0.05). WTs were rich in PD-1/PD-L1 expressing ICs. However, the tumor microenvironment of PA generally had low levels of PD-1/PD-L1 expression. In general, the expression of PD-1 in peripheral and central TCs was found to be significantly higher in malignant tumors than in benign ones (P = 0.002 and P = 0.003, respectively).

CONCLUSION

The simultaneous presentation of PD-1 and PD-L1 in TCs and ICs of SGTs, their significant association with disease severity as well as the positive correlation between these immune checkpoints may suggest the therapeutic potential of anti-PD-1 and anti-PDL-1 combinational immunotherapy for SGTs.

Immunological and biological dissection of normal and tumoral salivary glands

Salivary glands naturally play central roles in oral immunity. The salivary glands microenvironment inevitable may be exposed to exogenous factors consequently triggering the initiation and formation of various malignant and benign tumors. Mesenchymal stem cells are recruited into salivary gland microenvironment, interact with tumor cells, and induce inhibitory cytokines as well as cells with immunosuppressive phenotypes such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). The immune components and tumor immune responses in malignant and benign SGTs are still under investigation. Immune responses may directly play a limiting role in tumor growth and expansion, or may participate in formation of a rich milieu for tumor growth in cooperation with other cellular and regulatory molecules. Immune checkpoint molecules (e.g. PDLs, HLA-G and LAG3) are frequently expressed on tumor cells and/or tumor-infiltrating lymphocytes (TILs) in salivary gland microenvironment, and an increase in their expression is associated with T cell exhaustion, immune tolerance and tumor immune escape. Chemokines and chemokine receptors have influential roles on aggressive behaviors of SGTs, and thereby they could be candidate targets for cancer immunotherapy. To present a broad knowledge on salivary glands, this review first provides a brief description on immunological functions of normal salivary glands, and then describe the SGT's tumor microenvironment, by focusing on mesenchymal stem cells, immune cell subsets, immune checkpoint molecules, chemokines and chemokine receptors, and finally introduces immune checkpoint inhibitors as well as potential targets for cancer therapy.

Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial-myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

Pan-cancer Landscape of Programmed Death Ligand-1 and Programmed Death Ligand-2 Structural Variations

PURPOSE

Programmed cell death protein-1 (PD-1) receptor and ligand interactions are the target of immunotherapies for more than 20 cancer types. Biomarkers that predict response to immunotherapy are microsatellite instability, tumor mutational burden, and programmed death ligand-1 (PD-L1) immunohistochemistry. Structural variations (SVs) in PD-L1 (CD274) and PD-L2 (PDCD1LG2) have been observed in cancer, but the comprehensive landscape is unknown. Here, we describe the genomic landscape of PD-L1 and PD-L2 SVs, their potential impact on the tumor microenvironment, and evidence that patients with these alterations can benefit from immunotherapy.

METHODS

We analyzed sequencing data from cancer cases with PD-L1 and PD-L2 SVs across 22 publications and four data sets, including Foundation Medicine Inc, The Cancer Genome Atlas, International Cancer Genome Consortium, and the Oncology Research Information Exchange Network. We leveraged RNA sequencing to evaluate immune signatures. We curated literature reporting clinical outcomes of patients harboring PD-L1 or PD-L2 SVs.

RESULTS

Using data sets encompassing 300,000 tumors, we curated 486 cases with SVs in PD-L1 and PD-L2 and observed consistent breakpoint patterns, or hotspots. Leveraging The Cancer Genome Atlas, we observed significant upregulation in PD-L1 expression and signatures for interferon signaling, macrophages, T cells, and immune cell proliferation in samples harboring PD-L1 or PD-L2 SVs. Retrospective review of 12 studies that identified patients with SVs in PD-L1 or PD-L2 revealed > 50% (52/71) response rate to PD-1 immunotherapy with durable responses.

CONCLUSION

Our findings show that the 3'-UTR is frequently affected, and that SVs are associated with increased expression of ligands and immune signatures. Retrospective evidence from curated studies suggests this genomic alteration could help identify candidates for PD-1/PD-L1 immunotherapy. We expect these findings will better define PD-L1 and PD-L2 SVs in cancer and lend support for prospective clinical trials to target these alterations.

Approaches to the Management of Metastatic Adenoid Cystic Carcinoma

High rates of recurrence and distant metastasis are a foremost challenge in the management of adenoid cystic carcinoma (ACC), occurring in approximately 40% of all ACC patients. Despite the morbidity and mortality resulting from recurrent/metastatic (R/M) disease, there are no FDA-approved systemic agents for these patients. In this review, we summarize pertinent ACC pathophysiology and its implications for different systemic treatment regimens in R/M ACC. We review the evidence for the most widely used systemic agents - cytotoxic chemotherapy and tyrosine kinase inhibitors (TKIs) targeting VEGFR - in addition to immune checkpoint inhibitors and non-TKI biologic agents. Exciting emerging targets for R/M ACC, including inhibitors of Notch signaling, stemness, PRMT5, and Axl, are also discussed. Lastly, we review local therapies for small-volume lung disease in patients with oligometastatic ACC, specifically pulmonary metastasectomy and stereotactic body radiation therapy (SBRT). Future development of targeted molecular agents which exploit the underlying biology of this disease may yield novel therapeutic options to improve clinical outcomes in patients with R/M ACC.

Pulmonary Salivary Gland Tumor, Mucoepidermoid Carcinoma: A Literature Review

Pulmonary mucoepidermoid carcinoma (PMEC) is the most common malignant salivary gland tumor in the lungs and accounts for 0.1-0.2% of all lung malignancies in adults. It has no specific epidemiological or clinical characteristics. Correct diagnosis requires the combined examinations of images, laboratories, pathology, and immunohistochemistry (IHC) as well as molecular characteristics. PMEC tumors are characterized by squamous, intermediate, and mucus-secreting cells. Currently, histological appearance, mitotic frequency, cellular atypia, and necrocytosis allow the classification of PMEC into low grade or high grade. Molecular changes are crucial to pathological diagnosis. The driver of PMEC seems to be the fusion protein MECT1-MAML2 that is generated from a genetic mutation in t (11; 19) (q21; p13), while other gene mutations are also reported. However, no treatment of PMEC exists so far; surgical excision is still the primary treatment, while the efficacies of chemotherapy or radiotherapy are undefined. Tyrosine kinase inhibitor (TKI) therapy and immunotherapy showed to have significant therapeutic effects but require more investigation and better understanding. This review focuses on the clinical characteristics, imaging and pathologic features, immunohistochemical examination, mutation analysis, differential diagnosis, prognosis, and treatment of PMEC.

Prognostic value of PD-1, PD-L1 and PD-L2 deserves attention in head and neck cancer

Head and neck cancer has high heterogeneity with poor prognosis, and emerging researches have been focusing on the prognostic markers of head and neck cancer. PD-L1 expression is an important basis for strategies of immunosuppressive treatment, but whether it has prognostic value is still controversial. Although meta-analysis on PD-L1 expression versus head and neck cancer prognosis has been performed, the conclusions are controversial. Since PD-L1 and PD-L2 are two receptors for PD-1, here we summarize and analyze the different prognostic values of PD-1, PD-L1, and PD-L2 in head and neck cancer in the context of different cell types, tissue localization and protein forms. We propose that for head and neck cancer, the risk warning value of PD-1/PD-L1 expression in precancerous lesions is worthy of attention, and the prognostic value of PD-L1 expression at different subcellular levels as well as the judgment convenience of prognostic value of PD-1, PD-L1, PD-L2 should be fully considered. The PD-L1 evaluation systems established based on immune checkpoint inhibitors (ICIs) are not fully suitable for the evaluation of PD-L1 prognosis in head and neck cancer. It is necessary to establish a new PD-L1 evaluation system based on the prognosis for further explorations. The prognostic value of PD-L1, PD-L2 expression in head and neck cancer may be different for early-stage and late-stage samples, and further stratification is required.

Prognostic role of PD-L1 expression in patients with salivary gland carcinoma: A systematic review and meta-analysis

Background

Although programmed cell death-ligand 1 (PD-L1) has been recognized as a potential marker in several cancers, the relationship between PD-L1 expression and survival in patients with salivary gland carcinoma (SGC) has remained unclear. We aimed to evaluate the association of PD-L1 expression with clinicopathological features and prognosis in SGC patients.

Methods

The databases Ovid Medline, PubMed, Scopus, and EMBASE were searched for relevant studies that detected PD-L1 expression in SGC. The meta-analysis was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA), and the reporting recommendations for tumor marker prognostic studies (REMARK) was used to assess the quality of research eligible for this meta-analysis. Included studies were assessed using the Quality in Prognosis Studies (QUIPS) tool. Odds ratios (ORs) with 95% confidence interval (CI) were calculated to estimate the correlation between PD-L1 expression and clinicopathological features. Hazard ratios (HRs) with 95% CI were applied to assess the association between PD-L1 expression and survival outcomes of patients.

Results

A total of ten studies (including 952 patients with SGC) were evaluated. The meta-analysis showed that positive PD-L1 expression in SGC was significantly associated with male patients, older age, Tumor stage, lymph node metastasis, high pathological grade, and non-adenoid cystic carcinoma subtype. The pooled data demonstrated that high PD-L1 expression was associated with poor overall survival and disease-free survival. There was no significant correlation between PD-L1 expression and progression-free survival or disease-specific survival of SGC patients.

Conclusion

According to the meta-analysis, positive PD-L1 expression may play an important role as an effective marker of poor prognosis in patients with SGC. However, large-scale, prospective investigations are still needed to confirm the findings. The assessment of PD-L1 expression may aid in the personalized management of SGC.

Tissue and circulating PD-L2: moving from health and immune-mediated diseases to head and neck oncology

Amongst the chief targets of immune-checkpoint inhibitors (ICIs), namely the Programmed cell death protein 1 (PD-1)/PD-Ligands (Ls) axis, most research has focused on PD-L1, while to date PD-L2 is still under-investigated. However, emerging data support PD-L2 relevant expression in malignancies of the head and neck area, mostly in head and neck squamous cell carcinoma (HNSCC) and salivary gland cancers (SGCs). In this context, ICIs have achieved highly heterogeneous outcomes, emphasizing an urgent need for the identification of predictive biomarkers. With the present review, we aimed at describing PD-L2 biological significance by focusing on its tissue expression, its binding to PD-1 and RGMb receptors, and its impact on physiological and anti-cancer immune response. Specifically, we reported PD-L2 expression rates and significant clinical correlates among different head and neck cancer histotypes. Finally, we described the biology of soluble PD-L2 form and its potential application as a prognostic and/or predictive circulating biomarker.

Patterns of Tumor Infiltrating Lymphocytes in Adenoid Cystic Carcinoma of the Head and Neck

Simple Summary

Adenoid cystic carcinoma (ACC) is a rare tumor with late occurring metastases and recurrences, which makes it necessary for patients to be monitored closely even beyond the usual five years. So far, there is hardly any effective treatment in the palliative situation and trials on immunotherapeutic drugs have not been successful. We sought to find possible prognostic markers by analyzing patterns of tumor infiltrating immune cells and additionally to learn more about possible reasons for this lack of response to immunotherapy. It appears from our data that it is not relevant for prognosis if the tumor is infiltrated by immune cells. This might also be the reason that immunotherapies do not work in this particular disease, which suggests that ACC is not recognized by infiltrating immune cells. Therefore, the tumor would have to be made visible to the immune system, for example, through vaccinations.

Abstract

Adenoid cystic carcinoma (ACC) is a rare malignancy in the head and neck. The prognosis remains poor and late recurrences often occur after 5 years and later. To date, there are no reliable prognostic markers for ACC. In several solid tumors, tertiary lymphoid structures (TLS) are associated with improved survival. This study aims to investigate the role of distribution patterns of tumor infiltrating immune cells (TIL) in ACC. A cohort of 50 patients from three different cancer centers was available for analysis. Sections were stained for CD3, CD4, CD8 and CD20 and evaluated with regard to their distribution of TIL. Patterns were determined as infiltrated-excluded, infiltrated-inflamed and presence of tertiary lymphoid structures. About half of the cases showed an infiltrated-excluded TIL pattern and only a minority of six cases had TLS present within the tumor. Within the inflamed phenotype CD3+ cells were by far the most abundant lymphocyte subtype, and within this compartment, CD8+ T cells were predominant. There was no influence on overall or disease-free survival by any of the TIL patterns. This indicates that ACC is a tumor with very low immunogenicity and even abundance of lymphocytes does not seem to improve prognosis for this disease. Therefore, the observed lack of response towards immunotherapy is not surprising and other methods to induce recognition of ACC by the immune system must be found.

Mutational and immunologic Landscape in malignant Salivary Gland Tumors harbor the potential for novel therapeutic strategies

Salivary gland carcinomas (SGC) are rare (3-6 % of all head and neck cancers) and show biological heterogeneity depending on the respective histological subtype. While complete surgical resection is the standard treatment for localized disease, chemotherapy or radiation therapy are frequently insufficient for the treatment of unresectable or metastasized SGC. Therefore, new therapeutic approaches such as molecularly targeted therapy or the application of immune checkpoint inhibition enhance the treatment repertoire. Accordingly, comprehensive analyses of the genomic landscape and the tumor-microenvironment (TME) are of crucial importance in order to optimize and individualize SGC treatment. This manuscript combines the current scientific knowledge of the composition of the mutational landscape and the TME in SGCs harboring the potential for novel (immune-) targeted therapeutic strategies.

Biological Rationale and Clinical Evidence of Carbon Ion Radiation Therapy for Adenoid Cystic Carcinoma: A Narrative Review

Adenoid cystic carcinoma (ACC) is a rare, basaloid, epithelial tumor, arising mostly from salivary glands. Radiation therapy can be employed as a single modality for unresectable tumors, in an adjuvant setting after uncomplete resection, in case of high-risk pathological features, or for recurrent tumors. Due to ACC intrinsic radioresistance, high linear energy transfer (LET) radiotherapy techniques have been evaluated for ACC irradiation: while fast neutron therapy has now been abandoned due to toxicity concerns, charged particle beams such as protons and carbon ions are at present the beams used for hadron therapy. Carbon ion radiation therapy (CIRT) is currently increasingly used for ACC irradiation. The aim of this review is to describe the immunological, molecular and clinicopathological bases that support ACC treatment with CIRT, as well as to expose the current clinical evidence that reveal the advantages of using CIRT for treating ACC.

The Clinical Value of VDR and CTLA 4 in Evaluating the Prognosis of Invasive Duct Carcinoma of Egyptian Patients and their Benefit as a Target Therapy

OBJECTIVE

Breast cancer represents the second most common female malignancies worldwide  and  the most common in Egypt. The nuclear vitamin D receptor plays a role in the biology of cancer by affecting inflammatory microenvironment. The aim of this study is to evaluate the role of VDR and CTLA 4 in invasive duct carcinoma of Egyptian patients.

METHODS

This is a retrospective study that included 70 invasive duct carcinoma specimens retrieved from the archival material of Pathology Department, Faculty of medicine, Menoufia University, Egypt, spanning the period between January 2010 and December 2017. All cases were stained for VDR and CTLA 4 antibodies.

RESULTS

There is significant association between high VDR expression in tumor cells and parameters of good prognosis as low tumor stage (T1) and (N0) stage. On the other hand, there is significant association between low CTLA4 tumor expression and good prognostic parameters as low tumor stage (T1) and absent vascular invasion. Regarding lymphocyte expression, there is significant association between positive CTLA4 expression in lymphocytes and parameters of good prognosis as absent metastasis. High VDR tumor expression is the most independent prognostic factor on overall survival of breast carcinoma patients.

CONCLUSION

high VDR expression in tumor cells is associated with good prognostic parameters and is the most independent prognostic factor on overall survival  so it might be of benefit as a target therapy for Egyptian invasive duct carcinoma patients and VDR might augment the expression of CTLA-4, So tailored  immunotherapy might have an impact on invasive duct carcinoma patients.<br />.

Tumour-Infiltrating Lymphocytes (TILs) and PD-L1 Expression Correlate with Lymph Node Metastasis, High-Grade Transformation and Shorter Metastasis-Free Survival in Patients with Acinic Cell Carcinoma (AciCC) of the Salivary Glands

OBJECTIVES

The aim of this study was to assess the number of tumour-infiltrating lymphocytes (TILs) and the expression of Programmed Cell Death 1 Ligand 1 (PD-L1) in Acinic Cell Carcinoma (AciCC) of the salivary glands, to enable a correlation with clinico-pathological features and to analyse their prognostic impact.

METHODS

This single centre retrospective study represents a cohort of 36 primary AciCCs with long-term clinical follow-up. Immunohistochemically defined immune cell subtypes, i.e., those expressing T-cell markers (CD3, CD4 and CD8) or a B-cell marker (CD20) were characterized on tumour tissue sections. The number of TILs was quantitatively evaluated using software for digital bioimage analysis (QuPath). PD-L1 expression on the tumour cells and on immune cells was assessed immunohistochemically employing established scoring criteria: tumour proportion score (TPS), Ventana immune cell score (IC-Score) and combined positive score (CPS).

RESULTS

Higher numbers of tumour-infiltrating T- and B-lymphocytes were significantly associated with high-grade transformation. Furthermore, higher counts of T-lymphocytes correlated with node-positive disease. There was a significant correlation between higher levels of PD-L1 expression and lymph node metastases as well as the occurrence of high-grade transformation. Moreover, PD-L1 CPS was associated with poor prognosis regarding metastasis-free survival (p = 0.049).

CONCLUSIONS

The current study is the first to demonstrate an association between PD-L1 expression and lymph node metastases as well as grading in AciCCs. In conclusion, increased immune cell infiltration of T and B cells as well as higher levels of PD-L1 expression in AciCC in association with high-grade transformation, lymph node metastasis and unfavourable prognosis suggests a relevant interaction between tumour cells and immune cell infiltrates in a subset of AciCCs, and might represent a rationale for immune checkpoint inhibition.

Adenoid cystic carcinoma: a review of clinical features, treatment targets and advances in improving the immune response to monoclonal antibody therapy

The natural history of adenoid cystic carcinoma (ACC) is relentless, defined by treatment failure heralded by locoregional recurrence and distant metastatic disease. In this review, we present an update of clinical features, molecular classification, current targeted therapies, immune landscapes and novel treatment targets with their respective clinical trials. The presented results are defined by a lack of overall response rate and limited progression free survival, with restriction to stable disease. In addition, ACC is resistant to immune checkpoint inhibition due to low tumour immunogenicity and lack of PD-L1 expression. Here we present a new prospective research paradigm for ACC, including the potential to target prostate specific membrane antigen (PSMA) and the potential for manipulation of target receptors in the clinic. The presentation of this review aims to promote future research to improve response rates and outcomes for therapeutics undergoing clinical trial in ACC.

The Periphery of Salivary Gland Carcinoma Tumors Reveals a PD-L1/PD-1 Biomarker Niche for the Evaluation of Disease Severity and Tumor-Immune System Interplay

The treatment options for patients with advanced salivary gland cancers (SGCs) are limited. Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. However, the response to ICI immunotherapy is largely driven by the immune cell signatures within the tumor tissue and the para-tumoral tissue compartments. To date, there are no data on the expression of programed cell death protein-1/programed cell death protein-ligand 1 (PD-1/PD-L1) in SGC, which may enable the implementation of ICI immunotherapy for this disease. Thus, we performed an immunohistochemical analysis of PD-1 and PD-L1 expression in tumor cells and tumor-infiltrating immune cells (TIICs) in the tumor center and periphery of 62 SGC patients. The tumor periphery showed significantly higher expression of PD-L1 in tumor cells than in TIICs. Moreover, peripheral TIICs had significantly higher PD-1 expression than peripheral tumor cells. PD-1-positive tumor cells were detected exclusively in the tumor center of high-grade tumors, and most importantly, the presence of lymph node (LN) metastases and primary tumor stage significantly correlated with the presence of PD-L1-positive tumor cells in the tumor periphery. The PD-1/PD-L1 molecular signatures in SGC are clustered predominantly in the tumor periphery, reflect disease severity, and may predict the response to ICI immunotherapy in SGC patients.

The utility of TP53 and PIK3CA mutations as prognostic biomarkers in salivary adenoid cystic carcinoma

OBJECTIVES

Despite wide excision and post-operative irradiation, loco-regional and/or metastatic recurrence is a significant clinical problem in salivary adenoid cystic carcinoma (SACC). Reliable biomarkers are required to tailor post-treatment surveillance to patients at highest risk of recurrence. We sought to determine the utility of TP53 and PIK3CA mutations as prognostic biomarkers in SACC.

MATERIALS AND METHODS

DNA was extracted from archival tumour blocks of 145 SACC patients from 66 UK referral centres and sequenced for TP53 and PIK3CA mutations. Clinical, pathological and outcome data were analysed to determine the impact of the genomic alterations on disease recurrence and overall survival (OS).

RESULTS

TP53 and PIK3CA mutations were identified in 8% (10/121 successful analyses) and 2% (3/121) of cases, respectively. There were too few PIK3CA mutations in this cohort for informative further analysis. TP53-mutated SACC had significantly shorter median OS (5.3 vs. 16.3 years, p = 0.019) and lower 10-year survival (48% vs. 81%) compared with TP53 wild-type ACC. Solid-pattern histopathology was more frequent in TP53-mutated SACC (50% vs. 15%, p = 0.27).

CONCLUSION

TP53-mutated recurrent and metastatic SACC was associated with shorter OS, which was significant when combined with published genomic data sets. Stratifying by TP53 status, in addition to established clinical, pathological and genomic biomarkers, may usefully inform follow-up strategy.

Increased ERBB2 Gene Copy Numbers Reveal a Subset of Salivary Duct Carcinomas with High Densities of Tumor Infiltrating Lymphocytes and PD-L1 Expression

Salivary duct carcinoma (SDC) commonly expresses androgen receptor (AR) and HER2, giving rise to treatment implications. SDC may also express programmed-death-ligand-1 (PD-L1), a predictive marker of response to checkpoint inhibitors. PD-L1 can be associated with genomic instability and high density of tumor infiltrating lymphocytes (TILs). Evaluation of HER2 immunohistochemistry (IHC) in SDC is not standardized, and relationships between ERBB2 copy numbers, PD-L1 expression and TILs in SDC are unknown. We evaluated 32 SDCs for HER2, AR and PD-L1 expression (IHC), ERBB2 status (FISH) and TILs (slide review). HER2 was scored with three different systems (breast, gastric, proposed salivary gland). PD-L1 was evaluated with the combined positive score. Most patients were older men, presenting at advanced clinical stage with nodal or distant metastases. During follow-up (mean 5 years, range 6 months to 21 years), 25 of the 32 patients (78%) died of SDC. We propose a HER2 IHC scoring system which accurately predicts underlying ERBB2 amplification or increased copy numbers in SDC. Most tumors had increased ERBB2 copy numbers (19/32 amplification, 6/32 aneusomy), a finding associated with higher TIL densities (p = 0.045) and PD-L1 expression (p = 0.025). Patients with TILs ≥ 40% had better prognoses (Log-Rank p = 0.013), with TILs being favorable prognosticators in univariate analysis (Hazard ratio: 0.18, p = 0.024). A subset of SDCs with increased ERBB2 copy numbers have higher TILs and PD-L1 expression. TILs ≥ 40% are associated with better prognosis.

[Tumor microenvironment in salivary gland carcinomas: Consequences for new therapeutic concepts]

INTRODUCTION

Salivary gland carcinomas (SGCs) are rare tumors which represent a challenge for diagnosis and therapy due to their histological diversity and the different disease courses depending on the respective subtype. Little is known about the composition of the tumor microenvironment in SGCs. A more comprehensive understanding of the relevant molecular changes and immunological processes of the tumor and surrounding stroma could help to improve therapeutic efficiency, for example by adjuvant immunomodulation.

METHODS

This manuscript highlights recent studies analyzing the composition of the tumor microenvironment in salivary gland carcinomas.

RESULTS

The tumor microenvironment displays a significant diversity in the composition of immune cells among different tumor entities. In one third of the SGCs, an expression of cell surface molecule LAG3 on tumor infiltrating lymphocytes could be observed. LAG3-similar to CTLA‑4 and PD-1-inhibits cellular proliferation, activation, and homeostasis of antitumor-effective T cells. Especially, prognostically less favorable entities such as salivary duct carcinomas and adenocarcinomas NOS (not otherwise specified) yielded higher expressions.

CONCLUSIONS

LAG3 is particularly detectable in aggressive entities and advanced tumors. Hence, LAG3 inhibition poses a potential targeted therapy for advanced and metastatic SGCs.

Multicentre, retrospective study of the efficacy and safety of nivolumab for recurrent and metastatic salivary gland carcinoma

Although immune-checkpoint inhibitors (ICIs) are effective against various cancers, little is known regarding their role in salivary gland carcinoma (SGC) treatment. Therefore, we evaluated the efficacy and safety of nivolumab monotherapy in patients with recurrent and/or metastatic SGC. In this multicentre retrospective study, nivolumab (240 mg) was administered every 2 weeks. The overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety were examined; the correlation between treatment outcomes and clinicopathological factors was analysed. Twenty-four patients were enrolled; the most common histopathology was salivary duct carcinoma. Eleven tumours were PD-L1-positive; no tumour was microsatellite instability-high. The ORR was 4.2%, and the median PFS and OS were 1.6 and 10.7 months, respectively. One patient continued nivolumab for 28 months without disease progression. One patient showed grade 4 increase in creatine phosphokinase levels and grade 3 myositis. Biomarker analysis revealed significantly increased OS in patients with performance status of 0; modified Glasgow prognostic score of 0; low neutrophil-to-lymphocyte ratio, lactate dehydrogenase, and C-reactive protein; and high lymphocyte-to-monocyte ratio and in patients who received systemic therapy following nivolumab. Although nivolumab's efficacy against SGC was limited, some patients achieved long-term disease control. Further studies are warranted on ICI use for SGC.

Prognostic Value of Tumor Proportion Score in Salivary Gland Carcinoma

OBJECTIVE

Limited information is available regarding the role of programmed death ligand 1 (PD-L1) expression and CD8⁺ tumor-infiltrating lymphocyte (TIL) density in the tumor immune microenvironment (TIM) of patients with salivary gland carcinoma (SGC). This study aimed to assess the association between the prognosis of SGC patients and the probability of PD-L1 expression in tumor and/or immune cells using the tumor proportion score (TPS), mononuclear immune cell density score (MIDS), combined positive score (CPS), and CD8⁺ TIL density in the TIM.

STUDY DESIGN

Retrospective cohort study.

METHODS

We retrospectively reviewed 73 SGC patients treated with definitive surgery between 2000 and 2015. Immunohistochemical analysis was used to assess TPS, MIDS, CPS, and CD8⁺ TIL density, followed by prognostic evaluation of these immune-related parameters.

RESULTS

Histological grade was associated with TPS, MIDS, and CPS based on PD-L1 expression, and these scores exhibited a significant association with CD8⁺ TIL density. Patients with positive TPS had an unfavorable disease-free survival and overall survival. Multivariate analyses indicated that the TPS was a significant and independent prognostic factor.

CONCLUSION

Our results suggest that TPS might be a useful prognostic biomarker in SGC patients receiving definitive surgery. Laryngoscope, 131:E1481-E1488, 2021.

Programmed cell death-ligand 2: A neglected but important target in the immune response to cancer?

Programmed cell death-ligand 2 (PD-L2) is one of the two ligands of the programmed cell death-1 (PD-1) receptor, an inhibitory protein mainly expressed on activated immune cells that is targeted in the clinic, with successful and remarkable results. The PD-1/PD-Ls axis was shown to be one of the most relevant immunosuppressive pathways in the immune microenvironment, and blocking this interaction gave rise to an impressive clinical benefit in a broad variety of solid and hematological malignancies. Although PD-L2 has been historically considered a minor ligand, it binds to PD-1 with a two- to six-fold higher affinity as compared to PD-L1. PD-L2 can be expressed by immune, stromal, or tumor cells. The aims of this narrative review are to summarize PD-L2 biology in the physiological responses of the immune system and its role, expression, and clinical significance in cancer.

Salivary gland cancer in the era of immunotherapy: can we exploit tumor microenvironment?

INTRODUCTION

Salivary gland cancers (SGCs) consist of a rare family of neoplasms with varying histology and biological behavior. Therapeutic regimens have been relatively unchanged for decades. The recent successes of immunotherapy have raised hopes for the development of more effective strategies in SGC, thus emphasizing the role of tumor microenvironment (TME) in the design for more effective therapies.

AREAS COVERED

This review presents an overview of the current knowledge on the pathobiology of SGC TME and discusses the potential of immunotherapeutic targeting.

EXPERT OPINION

Most data on the role of TME in SGC carcinogenesis are derived from preclinical studies. Signaling cascades of immunotherapeutic interest, PD-1/PD-L1 and PD-1/PD-L2, are active in many SGCs and might be associated with biological behavior and prognosis. Immunotherapeutic attempts are very limited, but recent findings in other tumors on the role of exosomes and PD-L2 signaling suggest that TME of SGCs warrants further research, emphasizing larger cohorts, histology-based stratification, and standardized evaluation of immunomodulatory molecules, to explore the potential of targeting tumor stroma and its signaling cascades. Furthermore, combination of immunotherapies or immunotherapies with the antineoplastic agents targeting AR, HER2, and tyrosine kinases, recently introduced in SGC treatment, constitutes a promising approach for the future.

Prognostic impact of CD8-positive tumour-infiltrating lymphocytes and PD-L1 expression in salivary gland cancer

OBJECTIVES

Aim of the study was to evaluate the prognostic impact of CD8-positive (CD8⁺) tumour-infiltrating lymphocytes (TILs) and PD-L1 expression on the outcome of patients with malignant salivary gland neoplasms.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded tissue samples and clinicopathological data from patients treated for salivary gland carcinoma in a head and neck cancer centre were retrospectively retrieved. Immunohistochemical staining was applied on sections of 84 specimens of 12 different histological subtypes. Both CD8 and PD-L1 expression were rated by semi-automated cell counts by a digital image analysis programme. Survival analyses were performed by the log-rank test on the univariate level, and the Cox model was applied on the multivariate level. Associations between immunological markers and clinicopathological variables were estimated by the Pearson chi-squared test. Additionally, PD-1 was estimated as an exhaustion marker of CD8⁺ TILs.

RESULTS

Patients exceeding a tumour proportion score ≥5% regarding PD-L1 expression demonstrated a significantly decreased survival, as did individuals with an overall high CD8⁺ cell density. Particularly, high CD8⁺ cell counts in the invasive front of the respective tumour tissue significantly coincided with a poor outcome. Also, high numbers of CD8⁺ TILs significantly matched with a high quantity of PD-1⁺ TILs.

CONCLUSION

CD8⁺ TILs abundance in the peritumoural microenvironment correlates with impaired outcome of patients with salivary gland carcinoma. The simultaneous negative prognostic impact of PD-L1 expression and presence of PD-1⁺ TILs advocates an immune checkpoint-controlled mechanism of CD8⁺ TILs exhaustion for these tumours and paves the way for future treatment strategies.

Lymphocyte activation gene 3 (LAG3) protein expression on tumor-infiltrating lymphocytes in aggressive and TP53-mutated salivary gland carcinomas

Salivary gland carcinomas (SGCs) are rare and can be subdivided into distinct entities, some of which confer a poor prognosis. As targets for effective systemic therapy are warranted, some studies investigated the role of immune-checkpoint proteins PD-L1 and CTLA-4 in SGC. Our study depicts the expression of lymphocyte activation gene 3 (LAG3) in a test cohort and a larger validation cohort, totaling 139 SGCs. LAG3 is expressed on tumor-infiltrating lymphocytes (TILs), mediates T cell exhaustion and is subject to numerous currently recruiting clinical studies. Overall, one-third of SGCs were infiltrated by LAG3-expressing TILs with a strikingly high concordance between the test cohort and the validation cohort (30% and 28.2%, respectively). In the validation cohort, entity-wise LAG3 expression frequencies were highly variable. The highest rates were observed in salivary duct carcinoma (SDC; 66.7%) and adenocarcinoma not otherwise specified (ANOS; 50.0%). We observed LAG3 expression on effector T cells and in smaller frequencies also on FOXP3− T helper cells and FOXP3+ Tregs. LAG3 expression significantly correlated with advanced nodal metastases, cytotoxic T cell infiltrate and TP53 mutations. In the group of adenoid cystic carcinomas, LAG3 expression was also associated with a shorter event-free survival (EFS). Tumors with TP53 nonsense mutations (TP53 null type) exhibited higher LAG3 frequencies and a shorter EFS compared to TP53 wild type. This is the first report of LAG3 expression in SGC, a promising target for immunotherapy. LAG3 blockage could be distinctly applicable for SDC and ANOS, two SGC types with a particularly poor outcome.

The Immune Microenvironment and Neoantigen Landscape of Aggressive Salivary Gland Carcinomas Differ by Subtype

PURPOSE

Salivary gland carcinomas (SGC) are rare, aggressive cancers with high rates of recurrence and distant metastasis. These factors, and a lack of active systemic therapies, contribute to poor clinical outcome. Response rates with immune checkpoint blockade have been low, although clinical data remain sparse. To improve the efficacy of therapies, a more comprehensive understanding of relevant molecular alterations and immunologic processes is needed.

EXPERIMENTAL DESIGN

To characterize the immune microenvironment and neoantigen landscape of SGCs, we performed RNA sequencing (RNA-seq) in 76 tumors representing the three most lethal histologies: adenoid cystic carcinoma (ACC), myoepithelial carcinoma (MECA), and salivary duct carcinoma (SDC). We analyzed transcriptomic profiles, tumor-infiltrating immune cell populations, and measures of T-cell activation/dysfunction. In 37 cases also undergoing exome sequencing, we analyzed somatic mutations and neoantigens.

RESULTS

SDCs exhibited high levels of immune infiltration, with corresponding higher levels of T-cell dysfunction, and higher mutational load. In contrast, ACCs were characterized by an immune-excluded microenvironment, the presence of M2-polarized macrophages and myeloid-derived suppressor cells, and very low mutational load. MECAs were more heterogeneous, with both immune-low and immune-high phenotypes represented. Across all SGCs, levels of immune infiltration were associated with mutation- and fusion-derived neoantigens, and with aggressive clinical behavior.

CONCLUSIONS

These findings provide new insights into the immune microenvironment and neoantigen landscape of SGCs, showing that mechanisms of immune escape appear to differ by histology. These data nominate potential immunologic vulnerabilities and may help guide the next steps of investigation in precision immunotherapy for these difficult-to-treat cancers.

Treatment-induced changes of lymphocyte subsets in patients with adenoid cystic carcinoma of the head and neck

PURPOSE

Adenoid cystic carcinoma (ACC) of the head and neck is a rare and highly malignant tumor, characterized by perineural growth and early distant metastases. The composition of immune cells in the peripheral blood and the tumor microenvironment is critical to tumor growth and control. However, little is known about the frequency and function of the relevant immune cell subsets in this entity.

METHODS

In ACC patients (n = 11) and matched healthy donors (n = 11), the frequency of peripheral blood T and B cells was measured by flow cytometry at different treatment stages of disease (24 samples). Cells were further characterized by their expression of CCR7, PD-1, CD39 and CD73. Tumor-infiltrating lymphocytes (TIL) were analyzed by immunohistochemistry for ten patients and for three patients by flow cytometry.

RESULTS

CD4⁺ T cells had significantly lower frequency after radiotherapy (RT). All other cell frequencies, including T_reg, were stable through course of the disease. In B cells, CD73 was reduced after RT. CCR7 expression on T and B cells in patients with relapse/metastases (R/M) differed significantly from patients with active disease. PD-1 remained stable. T_reg were more present in TIL compared to peripheral blood.

CONCLUSION

Composition of lymphocyte subgroups behaves similar to squamous cell carcinoma in the head and neck, except for T_reg, which remained stable. Nevertheless, the CD4⁺/T_reg ratio was lower after RT, which could stand for an immunosuppressive effect in these patients. Therefore, it could be beneficial treating ACC with combined RT and immunomodulatory drugs.

Prognostic significance of PD-L2 expression in patients with oral squamous cell carcinoma-A comparison to the PD-L1 expression profile

BACKGROUND

Despite the observed association of increased PD-L1 expression in peripheral blood of oral squamous cell carcinoma (OSCC) patients with histomorphologic parameters, the role of the PD1 ligands-PD-L1 and PD-L2-is insufficiently understood. Aim of the study was to investigate whether the alterations of PD-L1 and PD-L2 expression in blood are associated with survival and could serve as immune monitoring parameter. Moreover, it should be analyzed if PD-L2 is differentially expressed in tissue and blood samples of OSCC patients compared to healthy controls and if there is an association of PD-L2 expression with histomorphologic and prognostic tumor parameters.

METHODS

PD-L2 mRNA expression was analyzed in tumors and healthy oral mucosa specimens and in corresponding peripheral blood samples of 48 OSCC patients and 26 healthy controls using RT-qPCR. A cutoff point (COP) was determined and a chi-square test (χ² test) was carried out. Survival analysis of PD-L2 and previously reported PD-L1 expression data was performed using Kaplan-Meier analysis (Log-rank test).

RESULTS

PD-L2 expression in tissue samples was significantly (P < 0.001) higher in OSCC patients compared to healthy controls. A significant association of PD-L2 expression above the COP (positive) with malignancy was ascertained (P < 0.001). A significant (P = 0.01) association of previously reported PD-L1 expression rates in peripheral blood with survival could be shown.

CONCLUSION

Peripheral blood PD-L1 expression might be a prognostic marker for OSCC patients and a possible parameter to monitor immune dysfunction in malign diseases. In the peripheral blood, PD-L1 might be more relevant for immune tolerance than PD-L2. Local PD-L2 expression in tissue samples might be useful as a diagnostic parameter for malignancy and could contribute to the immunosuppressive local microenvironment in OSCC.

PD-L2 expression is correlated with the molecular and clinical features of glioma, and acts as an unfavorable prognostic factor

Background: Gliomas are aggressive tumors with various molecular and clinical characteristics and exhibit strongly resistance to radio-chemotherapy. Programmed cell death 1 ligand 2 (PD-L2) is a cell surface protein, which was reported in many cancers, modulating cancer-associated immune responses, while the role of PD-L2 in gliomas remained unclear. Herein, we aimed to investigate the biological behaviors and clinical prognostic values of PD-L2 in gliomas.

Methods: Totally, we enrolled RNA sequencing data of 325 glioma samples from Chinese Glioma Genome Atlas (CGGA) as training cohort and RNA expression data of 1032 samples from The Cancer Genome Atlas (TCGA) dataset as validation cohort in this research. Then, the clinical and molecular characteristics, and the prognostic value of PD-L2 were analyzed.

Results: We found that PD-L2 expression level was significantly upregulated in higher grade glioma and IDH wild-type glioma. Receiver Operating Characteristic (ROC) analysis revealed that PD-L2 was a potential indicator of mesenchymal subtype. PD-L2 exhibited tight relationship with immune response and immune-modulating process in glioma. Moreover, PD-L2 expression level could predict unfavorable prognoses of patients independent of age, grade, IDH status and 1p/19q status.

Conclusions: Our study revealed that PD-L2 was closely related with inflammation and immune response. Patients with lower PD-L2 expression level tended to experience improved survival. Targeting PD-L2 may become a valuable approach for the treatment of gliomas in clinical practice.

High-affinity PD-1 molecules deliver improved interaction with PD-L1 and PD-L2

The inhibitory checkpoint molecule programmed death (PD)-1 plays a vital role in maintaining immune homeostasis upon binding to its ligands, PD-L1 and PD-L2. Several recent studies have demonstrated that soluble PD-1 (sPD-1) can block the interaction between membrane PD-1 and PD-L1 to enhance the antitumor capability of T cells. However, the affinity of natural sPD-1 binding to PD-L1 is too low to permit therapeutic applications. Here, a PD-1 variant with approximately 3000-fold and 70-fold affinity increase to bind PD-L1 and PD-L2, respectively, was generated through directed molecular evolution and phage display technology. Structural analysis showed that mutations at amino acid positions 124 and 132 of PD-1 played major roles in enhancing the affinity of PD-1 binding to its ligands. The high-affinity PD-1 mutant could compete with the binding of antibodies specific to PD-L1 or PD-L2 on cancer cells or dendritic cells, and it could enhance the proliferation and IFN-γ release of activated lymphocytes. These features potentially qualify the high-affinity PD-1 variant as a unique candidate for the development of a new class of PD-1 immune-checkpoint blockade therapeutics.

Programmed cell death-1 and programmed cell death ligand-1 antibodies-induced dysthyroidism

BACKGROUND

Monoclonal antibodies blocking the programmed cell death-1 (PD-1) or its ligand (PD-L1) are a group of immune checkpoints inhibitors (ICIs) with proven antitumor efficacy. However, their use is complicated by immune-related adverse events (irAEs), including endocrine adverse events (eAEs).

PURPOSE

We review the incidence, time to onset and resolution rate of dysthyroidism induced by PD-1/PD-L1 Ab, and the clinical, biological and radiological findings. We aim to discuss the potential mechanisms of PD-1/PD-L1 Ab-induced dysthyroidism, and to propose a management algorithm.

METHODS

We performed a literature search of available clinical trials regarding PD-1/PD-L1 Ab in the PubMed database. We selected all English language clinical trials that included at least 100 patients. We also present selected case series or reports, retrospective studies and reviews related to this issue.

FINDINGS

In patients treated with PD-1 Ab, hypothyroidism occurred in 2-10.1% and hyperthyroidism occurred in 0.9-7.8%. When thyroiditis was reported separately, it occurred in 0.34-2.6%. Higher rates were reported when PD-1 Ab were associated with other ICI or chemotherapy. The median time to onset of hyperthyroidism and hypothyroidism after PD-1 Ab initiation was 23-45 days and 2-3.5 months, respectively. Regarding PD-L1 Ab, hypothyroidism occurred in 0-10% and hyperthyroidism in 0.5-2% of treated patients. The average time to onset of dysthyroidism after PD-L1 Ab was variable and ranged from 1 day after treatment initiation to 31 months.

CONCLUSION

Dysthyroidism occurs in up to 10% of patients treated with PD-1/PD-L1 Ab. Hypothyroidism and reversible destructive thyroiditis are the most frequent endocrine adverse events (eAE) in PD-1/PD-L1 treated patients. Immune and non-immune mechanisms are potentially involved, independently of the presence of thyroid antibodies.

Programmed death-1 (PD-1) expression in cervical intraepithelial neoplasia and its relationship with recurrence after conization

OBJECTIVE

Impaired local cellular immunity contributes to persistent human papillomavirus (HPV) infection and development of cervical intraepithelial neoplasia (CIN). Programmed death-1 (PD-1) and its ligands PD-ligand-1 (L1) and PD-L2 are negative regulators of T cell activity in various cancers, but few studies exist. The aim of this study was to determine the clinicopathologic and immunologic parameters (PD-1, PD-L1, and PD-L2) related to the persistence/recurrence of CIN after conization.

METHODS

Medical records of 652 patients diagnosed with CIN and underwent conization were reviewed. The associations between clinicopathologic parameters (e.g., age, parity, initial HPV load, etc.) and persistence/recurrence of CIN were analyzed. Expression of PD-1, PD-L1, and PD-L2 was assessed on 100 conization specimens by immunohistochemistry (IHC) in women matched for propensity-score (50 with persistence/recurrence and 50 without).

RESULTS

Initial HPV load (>1,000 relative light unit) and positive margin were shown to be significantly associated with CIN persistence/recurrence (p=0.012 and p<0.001, respectively). Multivariate analysis showed that margin status was an independent predictor of persistence/recurrence (hazard ratio=8.86; 95% confidence interval=1.67-16.81; p<0.001). On IHC analysis, none of the patients expressed PD-L1. PD-1+ T cells were observed in 25 of 100 patients. Also, PD-1+ T cells were significantly correlated with increasing grade of CIN (p=0.031). In addition, patients with persistence/recurrence had increased expression of PD-1 compared with those without (36% vs. 14%, respectively; p=0.020). Although PD-L2 expression did not differ between 2 groups, it was significantly higher in patients with high-grade CIN compared to low-grade (34.7% vs. 12%, respectively; p=0.041).

CONCLUSION

Positive surgical margin and expression of PD-1+ T cells were associated with CIN persistence/recurrence after conization.