Oestrogen receptor β in adenoid cystic carcinoma of salivary glands

Single-cell RNA sequencing identifies a paracrine interaction that may drive oncogenic notch signaling in human adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (ACC) is a rare, biologically unique biphasic tumor that consists of malignant myoepithelial and luminal cells. MYB and Notch signaling have been implicated in ACC pathophysiology, but in vivo descriptions of these two programs in human tumors and investigation into their active coordination remain incomplete. We utilize single-cell RNA sequencing to profile human head and neck ACC, including a comparison of primary ACC with a matched local recurrence. We define expression heterogeneity in these rare tumors, uncovering diversity in myoepithelial and luminal cell expression. We find differential expression of Notch ligands DLL1, JAG1, and JAG2 in myoepithelial cells, suggesting a paracrine interaction that may support oncogenic Notch signaling. We validate this selective expression in three published cohorts of patients with ACC. Our data provide a potential explanation for the biphasic nature of low- and intermediate-grade ACC and may help direct new therapeutic strategies against these tumors.

A Contemporary Review of Molecular Therapeutic Targets for Adenoid Cystic Carcinoma

Simple Summary

Adenoid cystic carcinoma (ACC) is a salivary malignancy known for slow growth, a propensity for perineural spread, local recurrence following resection, and indolent distant metastases. Current treatments in recurrent/metastatic (R/M) ACC are generally of limited impact and often palliative in nature. Herein, we review the preclinical and clinical literature on molecular alterations in ACC with the potential for targeted therapeutics. We further review other molecular targets of ongoing investigation and active clinical trials for patients with ACC, offering a contemporary summary and insight into future therapeutic strategies.

Abstract

ACC is a rare malignant tumor of the salivary glands. In this contemporary review, we explore advances in identification of targetable alterations and clinical trials testing these druggable targets. A search of relevant articles and abstracts from national meetings and three databases, including PubMed, Medline, and Web of Science, was performed. Following keyword search analysis and double peer review of abstracts to ensure appropriate fit, a total of 55 manuscripts were included in this review detailing advances in molecular targets for ACC. The most researched pathway associated with ACC is the MYB–NFIB translocation, found to lead to dysregulation of critical cellular pathways and thought to be a fundamental driver in a subset of ACC disease pathogenesis. Other notable molecular targets that have been studied include the cKIT receptor, the EGFR pathway, and NOTCH1, all with limited efficacy in clinical trials. The ongoing investigation of molecular abnormalities underpinning ACC that may be responsible for carcinogenesis is critical to identifying and developing novel targeted therapies.

Multicentre clinicopathological study of adenoid cystic carcinoma: A report of 296 cases

Aims

Adenoid cystic carcinoma (ACC) is a distinctive tumour. Limited studies involving a large population have reported multicentre systematic analyses of the clinical, pathological and immunohistochemical (IHC) features of ACC as well as the potential role of IHC markers in the prognosis of ACC.

Methods and Results

The clinical, histopathological and IHC data of 296 cases obtained from two tertiary hospitals were analysed. The age at onset ranged from 12 to 87 years with a median age of 52 years. The male‐to‐female ratio was 1:1.3. Patients with ACC arising from the lacrimal gland were younger than those with tumours arising from other sites. Patients with tumours in the extra auditory canal and nasopharynx were older than those with tumours in other locations. Histopathologically, solid type ACC was the most frequent in the nasal cavity and paranasal sinus (6/51) group. Tumours arising from the oral cavity most commonly showed perineural invasion (10/60) and margin positivity (11/60). IHC analyses showed that CK8/18, CK7, CK14, epithelial membrane antigen and CD117 were expressed in 35/35 (100%), 87/88 (98.8%), 26/27 (96.2%), 42/43 (97.6%) and 113/120 (94.1%) patients, respectively. CK5/6, P63, smooth muscle actin, calponin and S100 were positively expressed in 73/73 (100%), 111/124 (89.5%), 38/43 (88.3%), 41/50 (82.0%) and 61/92 (66.3%) cases, respectively. S100 proteins were expressed in 54 (54/77) primary cases and two (2/9) metastatic cases (p = 0.013).

Conclusions

ACC is a distinctive tumour that mainly affects middle‐aged and elderly individuals, with a mild female predominance. Loss of expression of S100 proteins may be a poor prognostic factor associated with metastasis.

Risk of breast cancer in women after a salivary gland carcinoma or pleomorphic adenoma in the Netherlands

Salivary and mammary gland tumors show morphological similarities and share various characteristics, including frequent overexpression of hormone receptors and female preponderance. Although this may suggest a common etiology, it remains unclear whether patients with a salivary gland tumor carry an increased risk of breast cancer (BC). Our purpose was to determine the risk of BC in women diagnosed with salivary gland carcinoma (SGC) or pleomorphic adenoma (SGPA). BC incidence (invasive and in situ) was assessed in two nationwide cohorts: one comprising 1567 women diagnosed with SGC and one with 2083 women with SGPA. BC incidence was compared with general population rates using standardized incidence ratio (SIR). BC risk was assessed according to age at SGC/SGPA diagnosis, follow‐up time and (for SGC patients) histological subtype. The mean follow‐up was 7.0 years after SGC and 9.9 after SGPA diagnosis. During follow‐up, 52 patients with SGC and 74 patients with SGPA developed BC. The median time to BC was 6 years after SGC and 7 after SGPA. The cumulative risk at 10 years of follow‐up was 3.1% after SGC and 3.5% after SGPA (95% Confidence Interval (95%CI) 2.1%–4.7% and 2.6%–4.6%, respectively). BC incidence was 1.59 times (95%CI 1.19–2.09) higher in the SGC‐cohort than expected based on incidence rates in the general population. SGPA‐patients showed a 1.48 times (95%CI 1.16–1.86) higher incidence. Women with SGC or SGPA have a slightly increased risk of BC. The magnitude of risk justifies raising awareness, but is no reason for BC screening.

Sex Hormone Receptors in Benign and Malignant Salivary Gland Tumors: Prognostic and Predictive Role

The role of sex hormone receptors in human cancer development and progression has been well documented in numerous studies, as has the success of sex hormone antagonists in the biological therapy of many human tumors. In salivary gland tumors (SGTs), little and conflicting information about the role of the estrogen receptor alpha (ERα), progesterone receptor (PgR) and androgen receptor (AR) has been described and in most cases the use of sex hormone antagonists is not contemplated in clinical practice. In this study, we analyzed a panel of sex hormone receptors that have not been widely investigated in SGTs—ERα, PgR, AR, but also ERβ and GPR30—to define their expression pattern and their prognostic and predictive value in a case series of 69 benign and malignant SGTs. We showed the aberrant expression of AR in mucoepidermoid and oncocytic carcinoma, a strong relation between cytoplasmic ERβ expression and tumor grade, and a strong correlation between nuclear GPR30 expression and disease-free survival (DFS) of SGT patients.

Immunohistochemical and molecular profile of salivary gland cancer in children

BACKGROUND

Pediatric salivary gland carcinomas (SGCs) are very rare. They differ from the adult SGCs in terms of epidemiologic and clinical behavior, being generally limited only to selected histotypes (e.g. low-grade mucoepidermoid [LG-MEC] and acinic cell cancer [AcCC]) and characterized by very good outcome. Our aim was to investigate therapeutic targets on a series of pediatric SGCs by immunohistochemical and molecular analysis.

METHODS

A retrospective analysis was performed to search for cases of pediatric SGCs in the database of the Pediatric Oncology Unit at the Istituto Nazionale Tumori and in the Pathology database at the Gerhard-Seifert-Reference-Centre. The expressions of the most common tyrosine-kinase receptors (TKRs) reported in adult SGCs as EGFR, HER2, KIT and hormonal receptors (HRs) (estrogen α and β, progesterone as well as androgen receptors) were investigated. CRTC1/MAML2 and MYB/NFIB were also analyzed in MEC and adenoid cystic carcinoma cases, respectively.

RESULTS

Twenty-nine cases were identified: 22 MECs, 4 AcCCs, 1 adenoid cystic carcinoma (ACC), 1 adenocarcinoma not otherwise specified and 1 sialoblastoma. EGFR was the most expressed TKR, whilst HRs were negative in all cases except for ER-β in four cases of MEC. CRTC1/MAML2 was present in 15 out of 17 evaluable MEC cases and MYB/NFIB was identified in the ACC case.

CONCLUSIONS

The immunohistochemical and molecular profiles of pediatric SGCs analyzed in our series are similar to that observed in adults, especially for MEC, supporting a common biological background.

MTA1 regulation of ERβ pathway in salivary gland carcinoma cells

Although Metastatic-tumor antigen 1 (MTA1) is differentially expressed in metastatic cancer and coregulates the status and activity of nuclear receptors, its role upon estrogen receptor β (ERβ) - a potent tumor suppressor, remains poorly understood. Here we investigated whether MTA1 regulates the expression and functions of ERβ, an ER isoform predominantly expressed in salivary gland cancer cells. We found that the depletion of the endogenous MTA1 in the HSG and HSY salivary duct carcinoma cell lines enhances the expression of ERβ while MTA1 overexpression augmented the expression of ERβ in salivary duct carcinoma cells. Furthermore, MTA1 knockdown inhibited the proliferations and invasion of HSG and HSY cells. The noted ERβ downregulation by MTA1 overexpression involves the process of proteasomal degradation, as a proteasome inhibitor could block it. In addition, both MTA1 knockdown and ERβ overexpression attenuated the cell migration and inhibited the ERK1/2 signaling in the both cell lines. These findings imply that MTA1 dysregulation in a subset of salivary gland cancer might promote aggressive phenotypes by compromising the tumor suppressor activity of ERβ, and hence, MTA1-ERβ axis might serve a new therapeutic target for the salivary gland cancer.

Tissue microarray is a reliable method for immunohistochemical analysis of pleomorphic adenoma

OBJECTIVE

To determine the most adequate number and size of tissue microarray (TMA) cores for pleomorphic adenoma immunohistochemical studies.

STUDY DESIGN

Eighty-two pleomorphic adenoma cases were distributed in 3 TMA blocks assembled in triplicate containing 1.0-, 2.0-, and 3.0-mm cores. Immunohistochemical analysis against cytokeratin 7, Ki67, p63, and CD34 were performed and subsequently evaluated with PixelCount, nuclear, and microvessel software applications.

RESULTS

The 1.0-mm TMA presented lower results than 2.0- and 3.0-mm TMAs versus conventional whole section slides. Possibly because of an increased amount of stromal tissue, 3.0-mm cores presented a higher microvessel density. Comparing the results obtained with one, two, and three 2.0-mm cores, there was no difference between triplicate or duplicate TMAs and a single-core TMA.

CONCLUSIONS

Considering the possible loss of cylinders during immunohistochemical reactions, 2.0-mm TMAs in duplicate are a more reliable approach for pleomorphic adenoma immunohistochemical study.