Genetic rearrangements, hotspot mutations, and microRNA expression in the progression of metastatic adenoid cystic carcinoma of the salivary gland

Hypoxia induced cell dormancy of salivary adenoid cystic carcinoma through miR-922/DEC2 axis

BACKGROUND

Hypoxia has been shown to induce cancer cells to become dormant meanwhile these cells inclined to disseminate and eventually cause metastasis. However, the molecular mechanism is still elusive. The purpose is to explore whether dormancy-associated microRNAs (DmiRs) get involved in hypoxia-induced cell dormancy of salivary adenoid cystic carcinoma (SACC).

MATERIAL AND METHODS

This study performed multi-perspective investigation of the biological effects of miR-922/DEC2 on SACC based on clinical samples, 2D and 3D in vitro model and nude mice in vivo model, based on our previous study of overexpression of DEC2 inducing SACC cellular dormancy.

RESULTS

According to the existing microRNA array of SACC tissue, we found that miR-922 was upregulated in SACC tissue and was inversely correlated with DEC2, suggesting that miR-922 might participate in the activation of SACC cell dormancy as a DmiR. Then, we found miR-922 low SACC cells exhibited cell dormancy and a low level of fatty acid oxidation with propensity for lipid droplets accumulation through DEC2. Moreover, HIF1a downregulated the level of miR-922 to induce SACC cell dormancy. In addition, in xenografts of nude mice the inhibition of miR-922 attenuated the growth of primary tumor and the lung metastasis of SACC.

CONCLUSIONS

miR-922/DEC2 axis was necessary to hypoxia-induced cell dormancy and played an important role in the lipid metabolism reprogramming of SACC.

Malignant tumors of the external auditory canal: diagnosis, treatment, genetic landscape, biomarkers, and clinical outcome

Malignant tumors of the external auditory canal (EAC) are rare neoplasms that appear in the head and neck area. A common feature of these malignancies is their rarity, as well as their delayed diagnosis due to the appearance of non-specific symptoms that mimic various benign otologic conditions. The reported histological types of cancer of the external ear are: squamous cell carcinoma, basal cell carcinoma, malignant melanoma, Merkel cell carcinoma, angiosarcoma, adnexal carcinoma (including ceruminous adenocarcinoma and adenoid cystic carcinoma), and lymphoma (Lancet Oncol. 2005;6:411-20. doi: 10.1016/S1470-2045(05)70208-4). Several therapeutic interventions have been proposed, primarily orientated towards the cure of the patient, placing the surgical excision of the lesions at the tip of the spear. Subsequently and depending on the clinical stage and the pathological characteristics of the tumor, radiation, chemotherapy, a combination thereof, or some form of palliative treatment for particularly advanced cases, may be recommended. The aim of all the above-mentioned approaches is the complete resection of the mass with negative surgical margins along with lymph node dissection, the elimination of any residual disease or metastasis, and the improvement of survival. The anatomical complexity of the region will always remain a demanding challenge. Nevertheless, advances in the fields of ear microsurgery, imaging, radiation, molecular biology, and genomics have led to remarkable outcomes compared to the past, with a view to the patient's quality of life. Large, well-organized, and prospective studies with the participation of multiple centers in contrast to existing retrospective studies with a limited number of patients will help to establish universally accepted guidelines. The exploration of the molecular and genetic background of these cancers in conjunction with the search for new biomarkers and target molecules seems promising for providing upgraded and more personalized treatment modalities for the future.

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.

Metastatic Adenoid Cystic Carcinoma: Genomic Landscape and Emerging Treatments

OPINION STATEMENT

Adenoid cystic carcinoma (ACC) is a heterogeneous cancer that commonly develops in the salivary glands. Approximately 40 to 50% of patients with ACC develop recurrence and/or metastasis. Although most patients with ACC have slow-growing disease, a subset experiences aggressive disease with early visceral and/or bone metastasis. Thus far, there is no consensus on the best time to start palliative treatment in patients with indolent disease. The only systemic therapies available for recurrent or metastatic ACC are cytotoxic agents and multikinase inhibitors targeting vascular endothelial growth factor receptor, and both types of therapy have modest activity. Studies integrating proteomics, genomics, and clinical data have revealed distinct molecular ACC subtypes, ACC-I and ACC-II, with ACC-I generally associated with more aggressive disease biology. ACC-I tumors were enriched for NOTCH1-activating mutation and upregulation of MYC and MYC targets, while ACC-II tumors exhibited upregulation of TP63 and receptor tyrosine kinases. These findings highlight the importance of patient selection for surveillance and targeted therapy development in ACC. In recent clinical trials of targeted therapy in ACC, patients are being selected according to tumor molecular profile (e.g., presence of NOTCH-activating mutations), which represents a major advance in the field. Ongoing collaborative research focusing on the development of novel therapeutic strategies for ACC patients based on disease biology will increase the drug armamentarium and improve survival outcomes for these patients in dire need.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumours of the Ear

In the recently published 5th Edition of the World Health Organisation Classification of Head and Neck Tumours, there are relatively few changes to report in terms of nomenclature in lesions of ear and temporal bone and fewer developments in molecular pathogenesis in comparison to other sites, particularly in sinonasal tract. Ear and temporal bone tumours are rare and biopsy material is limited. As a result, resources in the literature are scarce with few large series, no controlled clinical trials and the approaches to staging and management are not standardised. New entities are difficult to characterise. The number of entries has, however, increased for tumours of the ear and temporal bone (thirteen) compared to the 4th Edition (eleven). Some lesions previously included in the 4th Edition considered to have no site-specific features have been excluded to be discussed elsewhere and other benign lesions that are specific to this site have been included. The tumours and tumour-like entities of ear and temporal bone are discussed here mindful that the chapter in the 5th edition better correlates disease processes with clinical information and imaging and as far as possible standardises nomenclature.

Rethinking the Definition of High Risk in Pediatric Salivary Gland Carcinoma

OBJECTIVE

Indications for adjuvant radiation in pediatric salivary gland carcinoma rely on high-risk criteria extrapolated from adult data. We sought to determine whether adult-derived high-risk criteria were prognostic in children aged ≤21 years or young adults aged 22 to 39 years.

STUDY DESIGN

Cross-sectional analysis of a hospital-based national registry.

SETTING

Patients were identified from the National Cancer Database between 2004 and 2015.

METHODS

High-risk criteria were defined as adenoid cystic histology, intermediate/high grade, T3/T4, positive margins, and/or lymph node involvement. Exact matching was used to adjust for differences in baseline characteristics between pediatric and young adult patients.

RESULTS

We identified 215 pediatric patients aged ≤21 years, 317 patients aged 22 to 30 years, and 466 patients aged 31 to 39 years. Within the pediatric cohort, there was no significant difference in overall survival (OS) between low- and high-risk groups (5-year OS, 100% vs 98.5%; P = .29). In contrast, within the young adult cohorts, there was a significant difference in OS between low- and high-risk groups in patients aged 22 to 30 years (5-year OS, 100% vs 96.1%; P = .01) and 31 to 39 years (5-year OS, 100% vs 88.5%; P < .001). When high-risk patients were matched 1:1 on high-risk criteria and race, pediatric patients were associated with better OS than those aged 22 to 30 years (P = .044) and those aged 31 to 39 years (P = .005).

CONCLUSION

Children have excellent OS, irrespective of adult-derived high-risk status. These findings underscore the need to understand how age modifies clinicopathologic risk factors.

Diagnostic and prognostic value of miRNAs on salivary gland tumors: a systematic review and meta-analysis

PURPOSE

Different levels of miRNA expression have been described in salivary gland tumors as a potential diagnostic marker and predictor of survival. We systematically reviewed the literature to assess the diagnostic and prognostic value of miRNAs on salivary gland tumors.

METHODS

An electronic search was conducted in PubMed, Scopus, Embase, Cochrane, and Web of Science databases. In the meta-analysis, we assumed random-effects model with adjusted hazard ratio (HR) and 95% confidence intervals (95% CI). For prognostic studies, the risk of bias was assessed by Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) and Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for diagnostic studies.

RESULTS

Gathered data from 1.131 patients in seven studies demonstrated that different levels of miRNA expression presented diagnostic and prognostic in SGTs. The meta-analysis showed that altered miRNA expression were associated with shortened survival (HR, 2.35, 95% CI, 1.77-3.10, P < .00001). For diagnostic meta-analysis, the overall pooled results for specificity and sensibility were 0.87-0.97 (95% CI, 0.72-1) and 0.68-0.91 (95% CI, 0.51-0.96), respectively.

CONCLUSION

MicroRNAs may be useful in prognostication of patients with SGTs; however, the diagnostic value of miRNAs in SGTs is still limited.

Prognosis and management of recurrent and/or metastatic head and neck adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a rare tumor, usually arising in the salivary gland, accounting for 1% of all head and neck cancers. ACC may have a long-term poor prognosis, as about 40% of radically treated patients will recur locoregionally and up to 60% will develop distant metastasis. Factors influencing risk of recurrence have been well studied, but few data exist about prognostic factors in Recurrent/Metastatic (RM) setting. Moreover, treatment of RM ACC is often a challenge for clinicians, in the context of a rare disease, which may have an indolent clinical behavior or less frequently a quicker growth and with a paucity of available clinical trials. This review critically analyzes pathological and molecular prognostic factors in RM ACC and make an overview on actual therapeutic choices and future direction of therapy. Recognized prognostic factors in RM ACC are the presence and site of distant metastasis (lung vs other), the presence of nodal metastasis and of extranodal extension, skull base recurrence, disease free interval, lymphovascular invasion, solid histotypes and grading of disease, and the presence of mutation of NOTCH1 family, PI3K, and TP53. Due to disappointing results with chemotherapy, new approaches are under study, also on the basis of biomolecular research. Ongoing clinical trials are evaluating treatment targeting MYB and NOTCH1 alterations, immunotherapy or combination of targeted treatments and immune checkpoint inhibitors.

Shallow whole genome sequencing of adenoid cystic carcinomas of the salivary glands identifies specific chromosomal aberrations related to tumor progression

BACKGROUND AND PURPOSE

Adenoid cystic carcinomas (ACC) are characterized by high rate of local recurrence and late distant metastasis. Chromosomal changes in the evolution from primary tumors to metastatic disease of ACC have not been appointed. Here we investigated the chromosomal alterations of 53 primary tumors from ACC patients with different progressive states by shallow whole genome sequencing to identify potential new markers for metastatic spread.

METHODS

Illumina paired-end libraries were generated using DNA from the primary tumor of 53 ACC patients. Fragmented DNA was end-repaired, A-tailed and multiplex sequencing adapters were ligated. Sequence data were mapped to HG19 and a copy-number analysis was conducted using the QDNAseq R package (version 1.10.0). Outliers were removed and data was smoothed by applying the circular binary segmentation algorithm implemented in the R package copynumber version 1.22.0. A modified chromosomal instability (CNI) score was used to analyze deletions and amplifications.

RESULTS

Cluster analysis of the whole genome sequencing revealed that the frequency of chromosomal aberrations were increased in ACC with local recurrence and distant metastases in comparison to ACC patients with no metastatic spread. Specifically, chromosome 6 and 12 and exclusively the entire chromosome 4 showed an increased frequency of chromosomal alterations with tumor progression.

CONCLUSION

Our data show a molecular evolution from primary tumors to local recurrences and distant metastases and pinpoint the critical chromosomal regions involved in this process. These regions should be in the focus of the search for therapeutic targets of progressive ACC.

Primary Adenoid Cystic Carcinoma of the Upper Anterior Mediastinum Mimicking a Thyroid Tumor: A Case Report and Review of Literature

Primary adenoid cystic carcinoma (ACC) of the upper anterior mediastinum mimicking a thyroid tumor has rarely been seen in clinical practice and lacks a standard of care therapy. Here, we report a 47-year old female patient with an ACC originated from the upper anterior mediastinum presenting as a thyroid gland tumor. The patient received gross surgical resection of the tumor and underwent post-surgical chemotherapy and radiotherapy. The patient was free from local recurrence 3-years following initial treatment, but developed multiple lung metastases. She remains under clinical observation without discomfort and is still followed as an outpatient. Here, we also summarized recent reports of similar cases with hope to provide some experience for future clinical practice.

An update on head and neck cancer: new entities and their histopathology, molecular background, treatment, and outcome

The head and neck region harbor numerous specialized tissues of all lineages giving rise to a plethora of different malignancies. In recent years, new types and subtypes of cancer has been described here due to the recognition of their histological and molecular characteristics. Some have been formally accepted in the most recent classifications from the World Health Organization (WHO) and American Joint Committee on Cancer (AJCC) as distinct diseases due to characteristics in clinical presentation, outcome, and treatment. In particular, this applies to malignancies of the salivary gland, sinonasal tract, and oropharynx. In this overview, we present the most recent developments in the classification, histopathological characteristics, and molecular features of head and neck cancer. The clinical and radiological characteristics, outcome, and treatment options including perspectives for targeted therapies, are discussed.