The expression of PD-L1 in salivary gland carcinomas

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.

Molecular Factors in Carcinoma Ex Pleomorphic Adenoma: Systematic Review and Meta-Analysis

OBJECTIVE

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor. Although multiple reviews have been published on salivary gland malignancies, it has been a decade since the last dedicated systematic review pertaining to CXPA alone was published. This study examines molecular factors in CXPA diagnosis.

DATA SOURCES

MEDLINE, CINAHL, Embase, Scopus, Web of Science (BIOSIS), Cochrane CENTRAL, Health Collection (Informit), OpenDOAR, and GreyNet International.

REVIEW METHODS

Systematic review and meta-analysis from inception to October 31, 2022 for all English language studies pertaining to "carcinoma ex pleomorphic adenoma." Predicted incidence of each biomarker was calculated with meta-analysis. Comparison against pleomorphic adenoma (PA) and salivary duct carcinoma (SDC) when reported within the same study are performed. Risk of bias performed with JBI tool for prevalence studies.

RESULTS

Of 19151 unique studies undergoing abstract screening, 55 studies (n = 1322 patients) underwent data analysis. Biomarkers with >3 studies were p53, HER2, AR, EGFR, PLAG1, ERBB, ER, PR, HMGA2, p16, p63, a-SMA, RAS, PTEN, PDL1, BRAF, PIK3CA, and c-kit. Highest incidence was seen in AR, EGFR, p16, and p53. Significant differences were demonstrated compared with PA and SDC. There was high heterogeneity and overall high risk of bias within studies.

CONCLUSION

Molecular factors are an area of interest in the diagnosis of CXPA. Our study results support examining CXPA as a discrete cohort in future targeted therapy trials. Laryngoscope, 134:1042-1053, 2024.

Pathogenesis Analysis of Salivary Gland Tumors Through the Expression of Programmed Death-Ligand 1 (PD-L1)

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm, followed by Warthin's tumor (WT). In addition to its high frequency, PA also shows metastasis and transformation towards malignancy as carcinoma ex-pleomorphic adenoma (CXPA). While the histogenesis of WT remains unclear, especially given the presence of lymphoid stroma around the developing tumor and the immunological interaction between them. Immune escape is a carcinogenesis mechanism of tumors to avoid the host immune system by producing PD-L1. This study was conducted to determine whether there is an immune escape through the expression of PD-L1 in salivary gland tumors. The tissue sections of PA, CXPA, and WT were stained with Hematoxylin Eosin and immunostained with a rabbit monoclonal recombinant anti-PD-L1 antibody. We observed immunopositive PD-L1 on the cell membrane with or without cytoplasm staining. PA and CXPA expressed PD-L1, accompanied by an anomaly expression of CXPA in several spots at the salivary gland at the surgical border. Therefore, PD-L1 is one of the PA pathways to transform into CXPA through immune escape. WT expressed PD-L1 in the cytoplasm and lymphoid stroma but not on the cell membrane. It is interpreted as positive constitutive, which may have the function of increasing tumor cell growth, while overexpressed PD-L1 in lymphoid stroma is thought to be associated with a poor prognosis of the tumor and is suspected to transform into malignancy, such as B-cell Lymphoma.

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).

Role of Surgical Pathologist for Detection of Immunooncologic Predictive Factors in Head and Neck Cancer

Immunotherapy has shown promising results in the treatment of recurrent and metastatic head and neck cancers. Antiprogrammed cell death (PD)-1 therapies have been recently approved in this setting and they are currently tested also in the treatment of locally advanced diseases and in the neoadjuvant setting. However, the clinical benefits of these treatments have been quite variable, hence the need to select those patients who may obtain the maximal efficacy through the identification of predictive biomarkers. Currently, PD-L1 immunohistochemical expression by tumor and immune cells is the most widely used predictive biomarker for immunotherapy in head and neck squamous cell carcinoma. Nevertheless, patients with PD-L1 - tumors may still respond to treatments, thereby emphasizing the need for the identification of other predictive biomarkers. In this review, we summarize the current data on histologic and molecular parameters that can be used to select patients with head and neck cancers for immunotherapy, with a focus on squamous cell carcinoma and salivary gland carcinomas.

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.

Sintilimab combined with chemotherapy successfully treated a patient with advanced submandibular gland tumor

Primary submandibular gland tumors are relatively rare. Due to its low incidence and broad spectrum phenotypic, biological and clinical heterogeneity types, a wide range of options have been developed to treat this tumor. To date, however, efficacious standard treatment regimens are lacking. Here, the authors present a case of a patient with an advanced submandibular gland tumor. Histological and imaging results diagnosed the case as stage IV submandibular gland adenocarcinoma with multiple metastases. The patient was subjected to systemic platinum-based chemotherapy combined with sintilimab. A primary lesion complete response was observed after six cycles of treatment. This case affirms the efficacy of the PD-1 inhibitor sintilimab combined with platinum-based chemotherapy as a first-line treatment for advanced submandibular gland tumors.

Efficacy and safety of anti-PD-1/PD-L1 therapy in the treatment of advanced colorectal cancer: a meta-analysis

Background

Immune checkpoint inhibitors have shown promise in microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) advanced colorectal cancer (CRC) immunotherapy, and many clinical trials have been conducted.

Objective

To evaluate the efficacy and safety of PD-1/PD-L1 inhibitors in advanced CRC.

Method

PubMed, Web of Science, Embase, and The Cochrane Library were searched for relevant studies up to September 2021. A retrospective cross-sectional data analysis was performed and Stata 16 software was used for analyses.

Results

Sixteen studies including 1503 patients were analyzed. The objective response rate (ORR) of anti-PD-1/PD-L1 was 23% (95% CI 0.14, 0.31); the overall 1-year survival rate (OSR) was 57% (95% CI 0.42, 0.73). The ORR of MSI-H/dMMR advanced CRC was 37% (95% CI 0.25, 0.48) and that of microsatellite stable/mismatch repair proficient (MSS/pMMR) disease was 11% (95% CI 0.06, 0.16). The ORR was 42% in the BRAF mutant subgroup and 19% in the RAS mutant group. The ORR was 14% in the PD-L1 ( +) subgroup and 32% in the PD-L1(-) subgroup. The rate of adverse effects was 85% (95% CI 0.80, 0.91).

Conclusion

Anti-PD-1/PD-L1 therapy in MSI-H/dMMR advanced CRC was associated with improved survival. Anti PD-1/PD-L1 combined with antiangiogenic drugs, targeted agents, or chemotherapy might be effective in MSS mCRC. Immunotherapy was effective for the BRAF mutant and KRAS/NRAS(RAS) mutant CRC. Low expression of PD-L1 was a potential predictive marker for positive response and outcome. The high incidence of adverse events at 85% was worthy of further investigation. Further analysis with a higher number of high-quality studies is needed to verify the conclusions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02511-7.

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.

Prolonged response to checkpoint inhibitor therapy in two metastatic mucoepidermoid salivary gland carcinoma cases: a research report

Salivary gland tumors (SGTs) are heterogeneous tumors that range from benign masses to aggressive high-grade carcinomas with distant metastatic potential and limited response to chemotherapy. Mucoepidermoid carcinoma (MEC) accounts for 10% of SGTs and has a poor prognosis. In this research report, we describe two cases of metastatic high-grade MECs with prolonged response to immune checkpoint inhibitor pembrolizumab. Case 1 presented with a left neck mass, and biopsy of the parotid mass revealed MEC. The patient underwent surgical resection and adjuvant chemoradiation therapy for stage IVB disease. Post-treatment, she was found to have brain and spinal metastases and was placed on pembrolizumab. Case 2 presented with a left neck mass, and biopsy of the right parotid gland revealed MEC. Further staging demonstrated metastatic disease in the lungs, and he was placed on pembrolizumab. Both cases of MEC demonstrated prolonged extracranial responses to pembrolizumab. Although both cases reported little to no PD-L1 expression, these results demonstrate immunotherapy efficacy in advanced/metastatic MEC.

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.

Atezolizumab Plus Chemotherapy vs. Chemotherapy in Advanced or Metastatic Triple-Negative Breast Cancer: A Cost-Effectiveness Analysis

Purpose: The IMpassion130 trial demonstrated the efficacy of adding atezolizumab to paclitaxel for advanced or metastatic triple-negative breast cancer (TNBC). The current study evaluated the cost-effectiveness of adding atezolizumab to nab-paclitaxel for TNBC from the perspective of Chinese health sector.

Methods: A partitioned survival model was implemented for patients with TNBC. The survival data were derived from IMpassion130 trial. Direct costs and utility values were collected from the Chinese Drug Bidding Database and published literatures. The primary analysis outcomes were quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were performed to observe model stability.

Results: In the base-case analysis, the ICER of atezolizumab plus nab-paclitaxel vs. nab-paclitaxel is respectively, $176,056/QALY, $118,146/QALY, and $323,077/QALY in the ITT, PD-L1(+) and PD-L1(–) group.

Conclusion: Adding atezolizumab to nab-paclitaxel could improve survival time significantly in the PD-L1-positive group, but it is not a cost-effective strategy compared to nab-paclitaxel monotherapy for Chinese patients with advanced or metastatic triple-negative breast cancer in the current economic context of China.

Incidence and Prognostic Significance of PD-L1 Expression in High-Grade Salivary Gland Carcinoma

Objective

PD-L1 is one of the predictors of immunotherapy efficacy. Our goal was to analyze its expression and prognostic significance in high-grade salivary gland carcinoma (SGC).

Methods

PD-L1 expression was evaluated using paraffin-embedded specimens from patients with surgically treated high-grade SGC, and it was scored by the tumor proportion score (TPS), combined positive score (CPS), and immune cell (IC) score. Associations between clinicopathological variables, disease-free survival (DFS), overall survival (OS) and PD-L1 expression were assessed.

Results

TPS≥1% occurred in 47 patients with an incidence of 43.1%, and it was significantly related to an advanced tumor stage. In patients with TPS<1%, TPS ranging from 1% to 20%, and TPS≥20%, the 5-year DFS rates were 36%, 26%, and 13%, respectively, and the difference was significant. In patients with TPS<1%, TPS ranging from 1% to 20%, and TPS≥20%, the 5-year OS rates were 49%, 24%, and 13%, respectively, and the difference was significant. CPS≥1 occurred in 87 patients with an incidence of 79.8%. IC scores of 0, 1, 2, and 3 were noted in 24 (22.0%), 37 (33.9%), 31 (28.4%), and 17 (15.6%) patients, respectively. Both CPS and IC scores had no impact on DFS or OS.

Conclusions

The expression of PD-L1 in tumor cells of high-grade SGCs was not uncommon, and it was significantly associated with tumor stage. PD-L1 expression in tumor cells rather than in immune cells indicated a poor prognosis.

Anticancer Effects of Sublingual Type I IFN in Combination with Chemotherapy in Implantable and Spontaneous Tumor Models

Salivary gland tumors are a heterogeneous group of neoplasms representing less than 10% of all head and neck tumors. Among salivary gland tumors, salivary duct carcinoma (SDC) is a rare, but highly aggressive malignant tumor resembling ductal breast carcinoma. Sublingual treatments are promising for SDC due to the induction of both local and systemic biological effects and to reduced systemic toxicity compared to other administration routes. In the present study, we first established that the sublingual administration of type I IFN (IFN-I) is safe and feasible, and exerts antitumor effects both as monotherapy and in combination with chemotherapy in transplantable tumor models, i.e., B16-OVA melanoma and EG.7-OVA lymphoma. Subsequently, we proved that sublingual IFN-I in combination with cyclophosphamide (CTX) induces a long-lasting reduction of tumor mass in NeuT transgenic mice that spontaneously develop SDC. Most importantly, tumor shrinkage in NeuT transgenic micewas accompanied by the emergence of tumor-specific cellular immune responses both in the blood and in the tumor tissue. Altogether, these results provide evidence that sublingual IFN holds promise in combination with chemotherapy for the treatment of cancer.

Patterns of care, toxicity and outcome in the treatment of salivary gland carcinomas: long-term experience from a tertiary cancer center

Background

Salivary gland carcinomas (SGC) cover a heterogeneous group of malignancies with a lack of data of high-level evidence.

Methods

Clinical data of 127 patients treated for SGC at a university cancer center between 2002 and 2017 were analyzed retrospectively. The association of clinicopathological characteristics, treatment modalities, adverse events, and outcome was assessed.

Results

Patients received surgery (n = 65), surgery followed by (chemo-)radiotherapy (n = 56), or primary (chemo-)radiotherapy (n = 6). Injury to the cranial nerves or their branches was the most frequent surgical complication affecting 40 patients (33.1%). Ten year overall and progression-free survival rates were 73.2% and 65.4%, respectively. Parotid tumor site, advanced tumor, and positive nodal stage remained independent negative prognostic factors for overall survival, loco-regional and distant tumor control in multivariate analysis.

Conclusions

Optimizing treatment strategies for SGC, depending on distinct clinicopathological factors, remains challenging due to the low incidence rates of the disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06652-5.

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.

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.

[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.

Tumor growth rate as a prognostic factor for metastatic or recurrent adenoid cystic carcinoma of the head and neck patients treated with carboplatin plus paclitaxel

PURPOSE

Large prospective studies of chemotherapy for metastatic or recurrent adenoid cystic carcinoma (ACC) of the head and neck are lacking due to the rarity of ACC. The aim of this study is to evaluate the efficacy of carboplatin plus paclitaxel toward ACC and perform an exploratory investigation of the prognostic factors to investigate the optimal strategy for metastatic or recurrent ACC.

METHODS

We retrospectively analyzed recurrent or metastatic ACC patients treated with carboplatin plus paclitaxel between April 2007 and September 2019 in our hospital. Objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) were evaluated, and an exploratory analysis of the prognostic factors was conducted.

RESULTS

A total of 26 ACC patients were enrolled. ORR and DCR were 11.5 and 76.9%; the median PFS and OS were 8.1 and 22.3 months, respectively. From the results of the multivariate analysis, higher (≥ 6%/month) tumor growth rate (TGR) was associated with worse PFS (hazard ratio [HR] 7.00, 95% CI 1.34-36.53, p = 0.02) and OS (HR 29.33, 95% CI 3.38-254.80, p < 0.01). The median PFS (10.6 vs. 6.6 months, log-rank p < 0.05) and OS (48.5 vs. 16.9 months, log-rank p < 0.01) were significantly shorter in patients with higher TGR.

CONCLUSIONS

Carboplatin plus paclitaxel showed modest efficacy for recurrent or metastatic ACC patients. Watchful waiting may be optimal for ACC patients with lower TGR. Systemic chemotherapy should be considered when TGR increases during active surveillance.

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.

Salivary duct carcinoma: Updates in histology, cytology, molecular biology, and treatment

Salivary duct carcinoma (SDC) is an aggressive subtype of primary salivary gland carcinoma, often with an advanced stage at presentation and high rates of metastasis and recurrence. It most commonly arises in the parotid gland of older men and microscopically resembles high-grade breast ductal carcinoma. While 50 years have lapsed since the first report of this entity, recent intensive studies have shed light on its biologic, genetic, and clinical characteristics. The diagnosis of SDC is aided by the immunohistochemical expression of androgen receptor (AR) coupled with its characteristic histomorphology. Fine-needle aspiration typically reveals cytologic features of high-grade carcinoma, and ancillary studies using cell block material can facilitate the specific diagnosis of SDC. In surgical specimens, certain histologic features are important prognostic factors, including nuclear pleomorphism, mitotic counts, vascular invasion, and the morphology at the invasion front. Several clinical studies have shown promising results using targeted therapy for AR and human epidermal growth factor receptor 2 (HER2), and the latest version of the National Comprehensive Cancer Network guidelines recommends the evaluation of AR and HER2 status before treatment. Recent molecular analyses have revealed multiple heterogeneous alterations in well-known oncogenes and tumor suppressor genes, including TP53, HRAS, PIK3CA, PTEN, and BRAF. Clinical trials of drugs targeting these genes may broaden the treatment options for SDC in the near future.

Phase I, first-in-human trial of programmed cell death receptor-1 (PD-1) inhibitor, JTX-4014, in adult patients with advanced, refractory, solid tumors

Background

Inhibition of programmed cell death receptor protein-1 (PD-1) has proven to be a highly effective strategy for immunotherapy of cancer. Approvals of both PD-1 and PD-L1 inhibitors [PD-(L)1i] in multiple tumor types are evidence of the durable benefits they provide to patients with cancer. In this first-in-human trial, we assessed the safety and tolerability of JTX-4014, a fully human antibody targeting PD-1.

Methods

JTX-4014 was administered to 18 patients with multiple solid tumor types who had not previously received a PD-(L)1i. The primary objectives were to evaluate the safety and tolerability of JTX-4014 and determine the maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Secondary objectives included evaluation of the pharmacokinetics (PK) of JTX-4014, anti-drug antibodies (ADA) against JTX-4014, and clinical activity.

Results

JTX-4014 was well tolerated and no new safety signals were identified as compared with other PD-1is. The MTD was not reached and the RP2D was selected, based on PK modelling and supportive safety data, to be 500 mg every 3 weeks or 1000 mg every 6 weeks. Clinical activity, based on RECIST v1.1 criteria, demonstrated an overall response rate of 16.7% (n = 3) with one complete and two partial responses and a disease control rate of 44.4% (n = 8). The responses occurred at different doses in patients with PD-L1 positive tumors and in tumor types that are not typically PD-1i responsive.

Conclusions

Further development of JTX-4014 is warranted as a monotherapy or in combination with other innovative cancer therapies.

Trial registration number

NCT03790488, December 31 2018.

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.

Systemic therapy in the management of recurrent or metastatic salivary duct carcinoma: A systematic review

BACKGROUND

Salivary duct carcinoma (SDC) is an aggressive subtype of salivary gland cancer. Approximately half of SDC patients will develop recurrences or metastases. Therapeutic palliative therapy is therefore often needed. The majority of SDC tumors expresses the androgen receptor (AR) and one-third expresses human epidermal growth factor receptor 2 (HER2), both are potential therapeutic targets. The aim of this paper is to systematically review and summarize the evidence on systemic palliative therapy for SDC and to provide treatment recommendations.

MATERIALS AND METHODS

Electronic libraries were systematically searched with a broad search strategy to identify studies where SDC patients received systemic therapy. Due to the rarity of SDC no restrictions were placed on study designs.

RESULTS

The search resulted in 2014 articles of which 153 were full-text analyzed. Forty-five studies were included in the analysis, which included in total 256 SDC patients receiving systemic therapy. Two phase 2 trials primarily including SDC patients were identified. The majority of the studies were case series or case reports, resulting in an overall low quality of available evidence. Based on studies including ≥ 5 SDC patients, objective responses to HER2 targeting agents were observed in 60-70%, to AR pathway agents in 18-53% and to chemotherapy in 10-50%.

CONCLUSION

For AR or HER2 positive SDC, agents targeting these pathways are the cornerstone for palliative treatment. Regarding chemotherapy, the combination of carboplatin combined with a taxane is best studied. Regarding other targeted agents and immunotherapy evidence is anecdotal, limiting formulation of treatment recommendations for these antineoplastic agents.

Efficacy of Nivolumab for Head and Neck Cancer Patients with Primary Sites and Histological Subtypes Excluded from the CheckMate-141 Trial

Background

In the CheckMate-141 trial, nivolumab conferred a survival benefit in patients with recurrent or metastatic refractory squamous cell carcinoma (SCC) head and neck cancer (HNC). Here, we examined the efficacy of nivolumab in patients with histological subtypes or primary sites of HNC not included in the CheckMate-141 trial.

Methods

This was a retrospective analysis of data collected prospectively from 97 patients who were treated with nivolumab for recurrent or metastatic HNC at our institution. The patients were assigned to three groups based on HNC primary site: 1) oral cavity, pharynx, and larynx, which were included in CheckMate-141 (n = 68), 2) nasopharynx (excluded in CheckMate-141, n = 7) and 3) other primary sites excluded in CheckMate-141 (n = 22) and assigned to two groups according to histological subtype: 1) SCC (included in CheckMate-141, n = 83) and 2) non-SCC (all sites excluded in CheckMate-141, n = 14). Survival outcomes and nivolumab treatment response were compared between the primary site and histological subgroups.

Results

The median number of nivolumab treatments was 7 cycles (range, 1-53 cycles) and the median follow-up time was 9.1 months (range, 0.66-33.0 months). There were no significant differences in response rates between the three primary site subgroups (CheckMate-141 sites 22%, nasopharynx 43%, others 18%; p=0) or the two histological subtype subgroups (SCC 25%, non-SCC 7%, p=0). Similarly, overall survival and progression-free survival were comparable for patients stratified by primary site or histological subtype.

Conclusion

No significant difference in response rates or survival outcomes was detected between nivolumab-treated HNC patients with primary sites and histological subtypes that were included versus excluded in the CheckMate-141 trial. These data provide a potential rationale for nivolumab therapy for all HNC patients in clinical practice.

Prognostic Impact of PD-L1 Expression in Malignant Salivary Gland Tumors as Assessed by Established Scoring Criteria: Tumor Proportion Score (TPS), Combined Positivity Score (CPS), and Immune Cell (IC) Infiltrate

Background: Malignant neoplasms of the salivary glands are rare, and therapeutic options are limited. Results from recently published studies indicate a possible use for checkpoint inhibition in a subset of patients, but there are no established criteria for programme cell death ligand 1 (PD-L1) scoring in salivary gland carcinomas (SGCs). Methods: In this retrospective study, we present a cohort of 94 SGC patients with full clinical follow-up. We included 41 adenoid cystic carcinomas (AdCC), 21 mucoepidermoid carcinomas (MEC), 16 acinic cell carcinomas (ACC), 12 adenocarcinomas, not otherwise specified (AC, NOS), 2 epithelial-myoepithelial carcinomas (EMC), one salivary duct carcinoma (SDC), and one carcinoma ex pleomorphic adenoma (CA ex PA). Subsequent histopathological analysis was performed with special emphasis on the composition of the immune cell infiltrate (B-/T-lymphocytes). We assessed PD-L1 (SP263) on full slides by established scoring criteria: tumor proportion score (TPS), combined positivity score (CPS) and immune cell (IC) score. Results: We identified significantly elevated CD3+, TP, CP, and IC scores in AC, NOS compared to AdCC, MEC, and ACC. CPS correlated with node-positive disease. Moreover, AC, NOS displayed IC scores of 2 or 3 in the majority (67%) of cases (p = 0.0031), and was associated with poor prognosis regarding progression-free (PFS) (p < 0.0001) and overall survival (OS) (p < 0.0001). CPS correlated with strong nuclear or null p53 staining in AC, NOS but not in other SGCs. Long-lasting partial remission could be achieved in one AC, NOS patient who received Pembrolizumab as third-line therapy. Conclusions: The current study is the first to investigate the use of established scoring criteria for PD-L1 expression in malignant salivary gland tumors. Our findings identify unique characteristics for AC, NOS among the family of SGCs, as it is associated with poor prognosis and might represent a valuable target for immune checkpoint inhibition.

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.

Expression of programmed death ligand 1 (PD-L1) is associated with metastasis and differentiation in gastric cancer

AIMS

Programmed death ligand 1 (PD-L1, CD274) has been reported to be expressed abnormally in many cancers, nevertheless, effect of PD-L1 on tumor cells remains unclear, especially in gastric cancer (GC). This study aimed to investigate the role of PD-L1 in metastasis and differentiation in GC.

MAIN METHODS

Immunohistochemistry was performed on 237 paired GC tissues. shPD-L1 cells were generated by lentivirus shRNA solution and PD-L1-overexpressing cells were constructed by pcDNA3.1. Expression of PD-L1 and E-cadherin in GC cells were detected by western blot.

KEY FINDINGS

PD-L1 expression was significantly lower in GC than that in adjacent normal tissues, especially in poorly differentiated and metastatic GC, but was positively correlated to survival time of patients. Moreover, PD-L1 ablation could decrease E-cadherin expression, promote cell migration and wound repair ability. In turn, overexpression of PD-L1 increased E-cadherin expression and inhibited wound repair ability. At the same time, All-trans retinoic acid (ATRA), which has the properties of pro-differentiation and inhibition of invasion and metastasis, upregulated the expression of PD-L1 and E-cadherin.

SIGNIFICANCE

These findings not only identify PD-L1 may have a positive role for the treatment of GC, but also implicate that ATRA combined PD-L1 antibody drugs may enhance anti-tumor Immunity in GC.