Expression of PTEN, Androgen Receptor, HER2/neu, Cytokeratin 5/6, Estrogen Receptor-Beta, HMGA2, and PLAG1 in Salivary Duct Carcinoma

The extent of androgen receptor and HER2 expression allows for targeted therapy in most cases of salivary duct carcinoma: analysis of clinical and histopathological data in a tertiary care center

PURPOSE

The incidence of salivary duct carcinoma (SDC) seems to be underestimated due to inaccurate classification. Further, the frequency of SDC patients with targeted therapy options according to current guidelines is unclear. Therefore, this study aimed at (a) describing the proportion of SDC among salivary gland carcinoma (SGC) before and after reclassification of cases initially classified as adenocarcinoma, not otherwise specified (ANOS); and (b) quantifying the frequency of SDC patients with targeted therapy options.

METHODS

All patients with SDC or ANOS treated in a tertiary care center between 1996 and 2023 were identified. Histopathological diagnosis was verified for patients primarily diagnosed with SDC and reviewed for patients initially diagnosed with ANOS. Clinical data for SDC patients were retrieved from clinical charts. Immunohistochemical (IHC) androgen receptor (AR) and HER2 staining was performed.

RESULTS

Among 46 SDC, 34 were primarily diagnosed as SDC and 12 had initially been classified as ANOS. The proportion of SDC among SGC was 12.1% and was rising when comparing the time periods 2000-2015 (7.1-11.5%) versus 2016-2023 (15.4-18.1%). Nuclear AR staining in > 70% of tumor cells was found in 56.8% and HER2 positivity (IHC 3 +) in 36.4% of cases. 70.5% of patients showed AR staining in > 70% of tumor cells and/or HER2 positivity and therefore at least one molecular target. 5-year overall and disease-free survival (DFS) were 62.8% and 41.0%. Multivariate Cox regression revealed positive resection margins (HR = 4.0, p = 0.03) as independent negative predictor for DFS.

CONCLUSIONS

The results suggest a rising SDC incidence and show that the extent of the AR and HER2 expression allows for targeted therapy in most SDC cases.

PTEN Deregulation Mechanisms in Salivary Gland Carcinomas

Among the tumour suppressor genes that affect critically cell functions and homeostasis, phosphatase and tensin homolog deleted in chromosome 10 (PTEN- gene locus: 10q21) regulates the PI3K/Akt/mTOR signalling pathway. PTEN is deleted, mutated or epigenetically hyper-methylated in a variety of human solid malignancies. Salivary gland carcinomas (SGCs) belong to the head and neck carcinomas (HNCs) super category of solid malignancies. Histo-pathologically, they demonstrate a significant diversity due to a variety of distinct and mixed subtypes. Genetically, they are characterized by a broad spectrum of gene and chromosomal imbalances. Referring specifically to suppressor genes, PTEN deregulation plays a critical role in signaling transduction in the corresponding SGC pre- and malignant epithelia modifying the response rates to potential targeted therapeutic strategies. In the current review, we explored the role of PTEN deregulation mechanisms that are involved in the onset and progression of SGCs.

Nectin-4 is frequently expressed in primary salivary gland cancer and corresponding lymph node metastases and represents an important treatment-related biomarker

Many locally advanced and metastatic salivary gland carcinomas (SGC) lack therapeutic targets. Enfortumab vedotin, an antibody-drug conjugate binding to Nectin-4, recently gained FDA approval for third-line urothelial carcinoma. Therefore, the aim of this study was to assess the expression of Nectin-4 in primary SGC and corresponding lymph node metastases and to correlate it with clinicopathological data. Immunohistochemical staining for Nectin-4 was performed for patients who had undergone surgery with curative intent for primary SGC of the parotid or submandibular gland in a tertiary referral center between 1990 and 2019. One hundred twenty-two primary SGC and twenty corresponding lymph node metastases were included. Nectin-4 was expressed in 80.3% of primary SGC with a mean Histo(H-)score of 61.2 and in 90.0% of lymph node metastases with a mean H-score of 75.6. A moderate or high Nectin-4 expression was found in 25.9% of salivary duct carcinomas (SaDu) and in 30.7% of adenoid cystic carcinomas (ACC). SaDu patients with a lower T-stage (p = 0.04), no loco-regional lymph node metastases (p = 0.049), no vascular invasion (p = 0.04), and no perineural spread (p = 0.03) showed a significantly higher mean Nectin-4 H-score. There was a statistical tendency towards a more favorable disease-free survival among SaDu patients with a higher Nectin-4 expression (p = 0.09). Nectin-4 is expressed in SGC and therefore represents a potential therapeutic target, especially in entities with a high rate of local recurrence and metastatic spread such as SaDu and ACC.

ERBB2 Amplification and HER2 Expression in Salivary Duct Carcinoma: Evaluation of Scoring Guidelines and Potential for Expanded Anti-HER2 Therapy

Salivary duct carcinoma (SDC) is aggressive with limited therapeutic options. A subset of SDC display human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry, and some show ERBB2 gene amplification. Guidelines for HER2 scoring are not firmly established. Recent advances in breast carcinoma have established a role for anti-HER2 therapies in lesions with low HER2 expression lacking ERBB2 amplification. Delineating HER2 staining patterns in SDC is critical for evaluating anti-HER2 treatments. In total, 53 cases of SDC resected at our institution between 2004 and 2020 were identified. Androgen receptor (AR) and HER2 immunohistochemistry and ERBB2 fluorescence in situ hybridization were performed in all cases. AR expression was scored for percentage positive cells and categorized as positive (>10% of cells), low positive (1%-10%), or negative (<1%). HER2 staining levels and patterns were recorded, scored using 2018 ASCO/CAP guidelines, and categorized into HER2-positive (3+ or 2+ with ERBB2 amplification), HER2-low (1+ or 2+ without ERBB2 amplification), HER2-very low (faint staining in <10% of cells), or HER2-absent types. Clinical parameters and vital status were recorded. Median age was 70 years, with a male predominance. ERBB2-amplified tumors (11/53; 20.8%) presented at lower pT stages (pTis/pT1/pT2; P = .005, Fisher exact test) and more frequently had perineural invasion (P = .007, Fisher exact test) compared with ERBB2 nonamplified tumors; no other pathologic features differed significantly by gene amplification status. In addition, 2+ HER2 staining by 2018 ASCO/CAP criteria was most common (26/53; 49%); only 4 cases (8%) were HER2-absent status; 3+ HER2 staining was found in 9 tumors, and all were ERBB2 amplified. Six patients with HER2-expressing tumors received trastuzumab therapy, including 2 with ERBB2-amplified tumors. Overall survival and recurrence-free survival did not differ significantly based on ERBB2 status. This work suggests that 2018 ASCO/CAP guidelines for HER2 evaluation in breast carcinoma could be applied to SDC. Our findings also show broad overexpression of HER2 in SDC raising the possibility that more patients may benefit from anti-HER2-directed therapies.

Role of Estrogen Receptor β, G-Protein Coupled Estrogen Receptor and Estrogen-Related Receptors in Endometrial and Ovarian Cancer

Ovarian and endometrial cancers are affected by estrogens and their receptors. It has been long known that in different types of cancers, estrogens activate tumor cell proliferation via estrogen receptor α (ERα). In contrast, the role of ERs discovered later, including ERβ and G-protein-coupled ER (GPER1), in cancer is less well understood, but the current state of knowledge indicates them to have a considerable impact on both cancer development and progression. Moreover, estrogen related receptors (ERRs) have been reported to affect pathobiology of many tumor types. This article provides a summary and update of the current findings on the role of ERβ, GPER1, and ERRs in ovarian and endometrial cancer. For this purpose, original research articles on the role of ERβ, GPER1, and ERRs in ovarian and endometrial cancers listed in the PubMed database have been reviewed.

Salivary duct carcinoma: A report of 70 FNA cases and review of the literature

BACKGROUND

Although usually recognized as malignant, fine-needle aspiration (FNA) biopsy of salivary duct carcinoma (SDC) has been confused with other primary salivary gland (SG) neoplasms. This article undertook an analysis of a large collection of SDC FNA cases to assess diagnostic accuracy, specificity, and cytopathology.

METHODS

Cytopathology files were searched for SDC with histopathologic validation. FNA biopsy smears were performed using standard techniques.

RESULTS

Seventy cases from 56 patients (M:F, 1.9:1; age range, 26-92 years; mean age, 65 years) met inclusion criteria. All had tissue confirmation of SDC. FNA sites included: parotid gland (42, 60% cases), neck (10), submandibular gland (7), pre-/post-auricular area (5), face/cheek (3), mediastinal lymph nodes (2), and clavicle (1). Aspirates were from primary (52, 74%), metastatic (12, 17%), and locally recurrent (6, 9%) neoplasms. FNA diagnoses included: SDC (19, 27%), favor/suspicious for SDC (7, 10%), high-grade carcinoma (11), adenocarcinoma (9), carcinoma (6), malignant (6), SG neoplasm (5), atypia (3), SDC versus another malignancy (2), and pleomorphic adenoma (2). Large polygonal cells in groups and single forms showed cribriforming, variable necrosis, pseudopapillae, and oncocytic change. Androgen receptor staining was positive in all cases.

CONCLUSIONS

FNA biopsy is accurate and reliable in classifying SDC as a malignant neoplasm, but much less so for identification as a specific tumor type. Using the Milan system, 86% of aspirates were classified as either malignant or suspicious for malignancy. A recurring pitfall includes sampling error in cases of SDC ex pleomorphic adenoma.

Steroid Receptors in Breast Cancer: Understanding of Molecular Function as a Basis for Effective Therapy Development

Breast cancer remains one of the most important health problems worldwide. The family of steroid receptors (SRs), which comprise estrogen (ER), progesterone (PR), androgen (AR), glucocorticoid (GR) and mineralocorticoid (MR) receptors, along with a receptor for a secosteroid-vitamin D, play a crucial role in the pathogenesis of the disease. They function predominantly as nuclear receptors to regulate gene expression, however, their full spectrum of action reaches far beyond this basic mechanism. SRs are involved in a vast variety of interactions with other proteins, including extensive crosstalk with each other. How they affect the biology of a breast cell depends on such factors as post-translational modifications, expression of coregulators, or which SR isoform is predominantly synthesized in a given cellular context. Although ER has been successfully utilized as a breast cancer therapy target for years, research on therapeutic application of other SRs is still ongoing. Designing effective hormone therapies requires thorough understanding of the molecular function of the SRs. Over the past decades, huge amount of data was obtained in multiple studies exploring this field, therefore in this review we attempt to summarize the current knowledge in a comprehensive way.

HER2 Positivity in Histological Subtypes of Salivary Gland Carcinoma: A Systematic Review and Meta-Analysis

Background

HER2 aberrations in salivary gland carcinomas (SGC) as well as benefit of HER2 directed therapy have been reported in small studies. However, reliable estimates of the prevalence of HER2 positivity in SGC and its various histological subtypes are lacking.

Objective

To assess the prevalence of HER2 positivity in histological subtypes of salivary gland carcinomas (SGC).

Methods

Studies were identified by a systematic review of the literature. Data on in situ hybridization (ISH) and immunohistochemistry (IHC) were extracted to derive pooled prevalence estimates calculated by a random effects model. Characteristics of the studies were extracted for subgroup analysis.

Results

Fifty studies including 3372 patients were identified, providing data on sixteen histological subtypes. Based on the meta-analysis, the estimated prevalence of HER2 positivity were 43% (95% CI: 36% – 51%) in salivary duct carcinoma (SDC), 39% (95% CI: 32% – 45%) in carcinoma ex pleomorphic adenoma (CEP), 17% (95% CI: 7.5% – 33%) in squamous cell carcinoma (SCC), 13% (95% CI: 7.6% – 21%) in adenocarcinoma NOS (ADC), 6.7% (95% CI: 0.17%-32%) in poorly differentiated carcinoma, 5.5% (95% CI: 2.9% – 9.6%) in mucoepidermoid carcinoma, 4.3% (95% CI: 1.4% – 13%) in myoepithelial carcinoma, 1.8% (95% CI: 0.04%-9.6%) in epithelial-myoepithelial carcinoma, 0.45% (95% CI: 0.0097% – 18%) in acinic cell carcinoma and 0.15% (0.037% – 5.4%) in adenoid cystic carcinoma. Estimates for five additional subtypes were assessed.

Conclusion

Prevalence of HER 2 positivity in SGC varies greatly based on histological subtype, with SDC, CEP, SCC, and ADC displaying the highest rates.

Androgen Deprivation Therapy for Patients with Androgen-Receptor-Positive Metastatic Salivary Duct Carcinoma: A Case Report and Review of the Literature

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy with high rates of recurrence and metastasis. There are no standard treatment options available for patients with recurrence and metastases. The case of a 61-year-old male with SDC of the left parotid gland is presented in this study. The results revealed that the patient’s tumour had strong positive staining for androgen receptor (AR) expression, mutations in HRAS and PIK3CA but not in other related genes, and no gene amplification of HER-2. After the primary therapy of parotidectomy with neck dissection and postoperative radiation, bone metastases were found in the ribs, pelvis and spine. Androgen deprivation therapy (ADT) involving combined androgen blockade (CAB) was effective as the first-line therapy for the patient’s metastases and resulted in a progression-free survival (PFS) of over 7 months to date. In conclusion, androgen deprivation therapy is recommended for patients with recurrent or metastatic SDC positive for androgen receptor expression.

Molecular Pathology of Salivary Gland Neoplasms: Diagnostic, Prognostic, and Predictive Perspective

Salivary gland neoplasms are an uncommon and widely heterogeneous group of tumors. In recent years, there has been considerable progress in efforts to reveal the molecular landscape of these tumors, although it is still limited and appears to be only the tip of the iceberg. Genomic aberrations, especially specific chromosomal rearrangements including CRTC1-MAML2 and CRTC3-MAML2 in mucoepidermoid carcinoma, MYB-NFIB and MYBL1-NFIB fusions in adenoid cystic carcinoma, PLAG1 and HMGA2 alterations in pleomorphic adenoma and carcinoma ex pleomorphic adenoma, ETV6-NTRK3 and ETV6-RET in secretory carcinoma, EWSR1-ATF1 and EWSR1-CREM in clear cell carcinoma, provide new insights into the molecular pathogenesis of various salivary gland neoplasms and help to better classify them. These genetic aberrations primarily serve as diagnostic tools in salivary gland tumor diagnosis; however, some also have promise as prognostic or predictive biomarkers. This review summarizes the latest developments in molecular pathology of salivary gland tumors with a focus on distinctive molecular characteristics.

Salivary Duct Carcinoma: An Aggressive Salivary Gland Carcinoma with Morphologic Variants, Newly Identified Molecular Characteristics, and Emerging Treatment Modalities

Salivary duct carcinoma (SDC) is a rare, aggressive salivary gland malignancy with significant mortality. Morphologically, most tumors are characterized by apocrine differentiation with a typical immunophenotype of androgen receptor positive/gross cystic disease fluid protein positive/estrogen receptor negative/progesterone receptor negative. Several morphologic variants of SDC exist, representing diagnostic pitfalls. Several differential diagnoses should be considered because prognosis, treatment, and management may be different from SDC. For SDC, current treatment strategies are aggressive and commonly include surgical excision with lymph node dissection and adjuvant radiotherapy. Continued research is examining the utility of androgen deprivation therapy and targeted molecular therapy.

HER2-positive metastatic, parotid salivary duct carcinoma treated with a trastuzumab/pertuzumab-based chemotherapy: A case report

This case highlights the rare entity, salivary duct carcinoma (SDC), which is difficult to diagnose and manage. It is the first published case of a metastatic, HER2-positive parotid SDC successfully treated by a dual anti-HER2 treatment associated to a chemotherapy.

The significance of tyrosine kinase receptor B and brain-derived neurotrophic factor expression in salivary duct carcinoma

Salivary duct carcinoma (SDC) is a high-grade salivary gland neoplasm. It may occur de novo or secondarily from pleomorphic adenoma (ex-PA), with secondary development accounting for more than 50% of the cases. In recent years, the expression of tyrosine kinase receptor B (TrkB), which is in the same family as HER2, has been confirmed in various types of carcinomas. However, there are a few studies on SDC. In order to examine the expression and role of TrkB in SDC, we investigated it. Immunohistochemistry was used to detect the expression of TrkB and its ligands, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) in 20 patients with SDC. The mRNA levels of TrkB, BDNF, and NT-4 were analyzed using quantitative polymerase chain reaction. TrkB was negative in 10 cases and positive in 10 cases, BDNF was negative in 11 cases and positive in 9 cases, and NT-4 was positive in all cases. There was a high number of TrkB-positive cases in the pT4 group and The H-score of TrkB was also significantly higher in the stage III and IV groups. There was a high number of BDNF-positive cases in the ex-PA group and Histo-score of BDNF had a trend of high expression in ex-PA. There were no significant differences or correlations in mRNA expression. Our results suggest that TrkB may be involved in SDC tumor growth.

The role of estrogen receptor beta in breast cancer

Breast cancer, a malignant tumor originating from mammary epithelial tissue, is the most common cancer among women worldwide. Challenges facing the diagnosis and treatment of breast cancer necessitate the search for new mechanisms and drugs to improve outcomes. Estrogen receptor (ER) is considered to be important for determining the diagnosis and treatment strategy. The discovery of the second estrogen receptor, ERβ, provides an opportunity to understand estrogen action. The emergence of ERβ can be traced back to 1996. Over the past 20 years, an increasing body of evidence has implicated the vital effect of ERβ in breast cancer. Although there is controversy among scholars, ERβ is generally thought to have antiproliferative effects in disease progression. This review summarizes available evidence regarding the involvement of ERβ in the clinical treatment and prognosis of breast cancer and describes signaling pathways associated with ERβ. We hope to highlight the potential of ERβ as a therapeutic target.

miR‑425‑5p is associated with poor prognosis in patients with breast cancer and promotes cancer cell progression by targeting PTEN

Breast cancer (BC) is the most common invasive cancer in women, and it imposes a heavy burden on patients. microRNAs (miRNAs/miRs) have been found to play an important role in the development of tumors, but their role in the malignant progression of BC is unclear. In the present study, the expression level of miR‑425‑5p was examined in patients with BC, and its association with prognosis was investigated. In vitro experiments were performed to examine role of miR‑425‑5p in the development of BC cells. A downstream target gene of miR‑425‑5p was predicted using a miRNA target prediction tool and validated with a luciferase reporter assay. It was found that miR‑425‑5p expression was increased in BC tissues and cell lines, and was associated with tumor size, clinical stage, lymph node metastasis, distant metastasis and poor overall survival in patients with BC. Knockdown of miR‑425‑5p in BC cell lines inhibited proliferation and migration. PTEN was identified as a downstream target gene of miR‑425‑5p. Overexpression of PTEN was demonstrated to partially inhibit the promotional effect of miR‑425‑5p on cell proliferation and migration. Taken together, miR‑425‑5p is associated with poor prognosis, and promotes cell proliferation and migration via PTEN. Thus, miR‑425‑5p may serve as a therapeutic and prognostic marker for BC.

Androgen receptor immunohistochemistry in salivary duct carcinoma: a retrospective study of 188 cases focusing on tumoral heterogeneity and temporal concordance

Salivary duct carcinoma (SDC) is a high-grade salivary gland carcinoma that is associated with frequent metastasis and poor outcome. Androgen receptor (AR) immunoexpression in SDC is reported in 69% to 100% of SDC. Androgen deprivation therapy (ADT) has shown a response rate of 18% to 42% in SDC. Therefore, AR immunoexpression may serve as a diagnostic and predictive marker for ADT response in SDC. We investigated AR immunopositivity and staining pattern in a large retrospective cohort of 188 SDCs from 163 patients, including 22 paired primary and metastatic SDCs from the same patients, focusing specifically on staining heterogeneity and concordance. A control cohort of 61 non-SDC salivary gland carcinomas was also included. AR immunopositivity defined as ≥1% of tumor cell nuclear staining was found in 94% (177/188) of SDCs, including 95% of primary tumors, 100% of regional metastases, and 90% of distant metastases. Most of the cases (75%, 86/114) showed homogeneous and diffuse AR positivity. However, a subset (25%) exhibited focal or heterogeneous AR staining pattern. Although most metastases (21/22, 95%) had concordant AR expression with the primary tumors, one treatment-naïve tumor (5%) had complete loss of AR immunoexpression in the metastasis without detectable molecular alterations in AR or AR co-regulators. AR positive staining in non-SDC salivary carcinomas was infrequent (15%, 9/61), and mostly heterogeneous or focal. AR immunoexpression is highly prevalent in SDC, in both primary (94%) and metastatic tumors (93%). The cumulative AR immunopositivity rate in SDC is 90% based on data from the current study and previous literature. A small subset may show intratumoral AR heterogeneity and discordant AR expression in metastasis. AR immunoexpression may be seen in non-SDC salivary gland carcinomas but it is uncommon and usually focal.

PD-L1 expression by immunohistochemistry in salivary duct carcinoma

BACKGROUND

Immune checkpoint inhibitors play an increasing role in oncologic care. PD-L1 expression is associated with survival and predicts response to PD-1 or PD-L1 inhibitors in a variety of tumors. Our aim is to evaluate the frequency and prognostic significance of PD-L1 expression in salivary duct carcinoma.

DESIGN

We retrospectively evaluated the expression of PD-L1 by two different antibodies (PD-L1 28-8 and PD-L1 22C3) in salivary duct carcinomas. PD-L1 expression in at least 1% of tumor cells was considered immunoreactive. Kaplan-Meier analysis was performed to determine the impact of PD-L1 expression on survival; differences between survival curves were assessed by the chi-square test, and pairwise comparisons of factors were assessed with the log-rank test.

RESULTS

A total of 113 patients' specimens were evaluated. Seventy-six (76%) of the patients were male. Mean age at time of presentation was 61.2 (SD = 12.4) years. PD-L1 expression was found in 26% of the samples. Median follow-up time was 36.6 months (range = 1.4-249 months). Overall survival at 3, 5 and 10 years were 52.6%, 37.9% and 25.6%, respectively. There was no statistical difference in survival between patients with PD-L1-immunoreactive tumors and those without, regardless of which antibody was used (chi² result for all plots: p = 0.53; log rank test for pairwise comparison: p > 0.256).

CONCLUSION

In our analysis, PD-L1 expression occurred in a small proportion of salivary duct carcinomas, usually at low levels, and did not correlate with survival. Its predictive value and utility in selecting patients with salivary duct carcinoma who might benefit from PD-1/PD-L1 inhibitors warrants further investigation.