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.

Intratumoral Abundance of M2-Macrophages is Associated With Unfavorable Prognosis and Markers of T-Cell Exhaustion in Small Cell Lung Cancer Patients.

Small cell lung cancer (SCLC) accounts for about 10% to 15% of lung cancer cases. Unlike non-SCLC, therapy options for SCLC are limited, reflected by a 5-year survival rate of about 7%. At the same time, the rise of immunotherapeutic approaches in cancer therapy has rationalized to account for inflammatory phenotypes in tumors. However, the composition of the inflammatory microenvironment in human SCLC is poorly understood to date. In our study, we used in-depth image analysis of virtual whole-slide-images of 45 SCLC tumors and evaluated different markers of M2-macrophages (CD163 and CD204) together with global immunologic markers (CD4, CD8, CD68, CD38, FOXP3, and CD20) and characterized their abundance intratumorally using quantitative image analysis, combined with a deep-learning model for tumor segmentation. In addition, independent scoring, blinded to the results of the computational analysis, was performed by an expert pathologist (A.Q.) of both CD163/CD204 and PD-L1. To this end, we evaluated the prognostic relevance of the abundance of these cell types to overall survival. Given a 2-tier threshold of the median of the M2 marker CD163 within the study population, there was a 12-month overall survival rate of 22% (95% CI, 10%-47%) for patients with high CD163 abundance and 41% (95% CI, 25%-68%) for patients with low CD163 counts. Patients with increased CD163 had a median overall survival of 3 months compared to 8.34 months for patients with decreased CD163 counts (P = .039), which could be confirmed by an expert pathologist (A.Q., P = .018). By analyzing cases with increased CD163 cell infiltrates, a trend for higher FOXP3 counts and PD-L1 positive cells, together with increased CD8 T-cell infiltrates, was observed, which could be confirmed using an independent cohort at the transcriptional level. Together, we showed that markers of M2 were associated with unfavorable outcome in our study cohort.

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.

KEAP1/NFE2L2 Pathway Signature Outperforms KEAP1/NFE2L2 Mutation Status and Reveals Alternative Pathway-Activating Mutations in NSCLC.

INTRODUCTION: Activation of the antioxidant KEAP1/NFE2L2 (NRF2) pathway leads to increased glutamine dependence and an aggressive phenotype in NSCLC. Because this pathway has been explored as a clinical target, we developed a transcriptomic signature for identifying KEAP1/NFE2L2-activated tumors. METHODS: A total of 971 NSCLC samples were used to train an expression signature (K1N2-score) to predict KEAP1/NFE2L2 mutations. There were 348 in-house NSCLCs that were analyzed using a NanoString expression panel for validation. RESULTS: The 46-gene K1N2 score robustly predicted KEAP1/NFE2L2 mutations in the validation set irrespective of histology and mutation (area under the curve: 89.5, sensitivity: 90.2%), suggesting that approximately 90% of KEAP1/NFE2L2 mutations are pathway-activating. The K1N2-score outperformed KEAP1/NFE2L2 mutational status when predicting patient survival (score p = 0.047; mutation p = 0.215). In K1N2 score-positive but KEAP1/NFE2L2 wild-type samples, enrichment testing identified SMARCA4/BRG1 and CUL3 mutations as mimics of KEAP1/NFE2L2 mutations. CONCLUSIONS: The K1N2-score identified KEAP1/NFE2L2-activated NSCLC by robustly detecting KEAP1/NFE2L2mut cases and discovering alternative genomic activators. It is a potential means for selecting patients with a constitutively active KEAP1/NFE2L2 pathway.

The extracellular matrix landscape in salivary gland carcinomas is defined by cellular differentiation via expression of three distinct protein modules.

The extracellular matrix (ECM) is an integral part of the tumor microenvironment of carcinomas. Even though salivary gland carcinomas (SGCs) display a range of tumor cell differentiation and distinct extracellular matrices, their ECM landscape has not been characterized in depth. The ECM composition of 89 SGC primaries, 14 metastases, and 25 normal salivary gland tissues was assessed using deep proteomic profiling. Machine learning algorithms and network analysis were used to detect tumor groups and protein modules that explain specific ECM landscapes. Multimodal in situ studies to validate exploratory findings and to infer a putative cellular origin of ECM components were applied. We revealed two fundamental SGC ECM classes which align with the presence or absence of myoepithelial tumor differentiation. We describe the SGC ECM through three biologically distinct protein modules that are differentially expressed across ECM classes and cell types. The modules have a distinct prognostic impact on different SGC types. Since targeted therapy is rarely available for SGC, we used the proteomic expression profile to identify putative therapeutic targets. In summary, we provide the first extensive inventory of ECM components in SGC, a difficult-to-treat disease that encompasses tumors with distinct cellular differentiation. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

[Diagnostics and treatment of secondary malignancies of the parotid gland-An overview]. / Diagnostik und Therapie sekundärer Malignome der Ohrspeicheldrüse ­ eine Übersicht.

BACKGROUND: Secondary malignancies of the parotid gland frequently have a cutaneous origin and the incidence in central Europe is increasing. OBJECTIVE: The aim of this review article was to present the epidemiology, (differential) diagnostics and treatment of secondary malignancies of the parotid gland. MATERIAL AND METHODS: A literature search of the current guidelines and evidence was carried out in the web-based databank PubMed. RESULTS: The incidence of secondary malignancies of the parotid gland seems to be increasing in Europe, mainly due to a rising incidence of metastases of cutaneous squamous cell carcinomas. Except for malignant lymphomas, parotidectomy is the treatment of choice in the curative situation. In the absence of clear evidence, in the case of an intact facial nerve lateral or total parotidectomy with ipsilateral neck dissection seems to be indicated, depending on the entity of the secondary malignancy. CONCLUSION: The differential diagnostics of squamous cell carcinoma (in) of the parotid gland can be complicated. When a squamous cell carcinoma of the parotid gland is diagnosed for the first time, a dermatological full body examination and a detailed medical history should be taken with respect to skin tumors of the head and neck region. In addition to surgical treatment of the parotid gland and neck, adjuvant radiotherapy is usually indicated.

Multi-Class Cancer Subtyping in Salivary Gland Carcinomas with MALDI Imaging and Deep Learning.

Salivary gland carcinomas (SGC) are a heterogeneous group of tumors. The prognosis varies strongly according to its type, and even the distinction between benign and malign tumor is challenging. Adenoid cystic carcinoma (AdCy) is one subgroup of SGCs that is prone to late metastasis. This makes accurate tumor subtyping an important task. Matrix-assisted laser desorption/ionization (MALDI) imaging is a label-free technique capable of providing spatially resolved information about the abundance of biomolecules according to their mass-to-charge ratio. We analyzed tissue micro arrays (TMAs) of 25 patients (including six different SGC subtypes and a healthy control group of six patients) with high mass resolution MALDI imaging using a 12-Tesla magnetic resonance mass spectrometer. The high mass resolution allowed us to accurately detect single masses, with strong contributions to each class prediction. To address the added complexity created by the high mass resolution and multiple classes, we propose a deep-learning model. We showed that our deep-learning model provides a per-class classification accuracy of greater than 80% with little preprocessing. Based on this classification, we employed methods of explainable artificial intelligence (AI) to gain further insights into the spectrometric features of AdCys.

CD138 Is Expressed in Different Entities of Salivary Gland Cancer and Their Lymph Node Metastases and Therefore Represents a Potential Therapeutic Target.

Advanced salivary gland carcinomas (SGC) often lack therapeutic options. Agents targeting CD138 have recently shown promising results in clinical trials for multiple myeloma and a preclinical trial for triple-negative breast cancer. Immunohistochemistry for CD138 was performed for all patients who had undergone primary surgery for SGC with curative intent. Findings were validated using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging. Overall, 111 primary SGC and 13 lymph node metastases from salivary duct carcinomas (SaDu) were evaluated. CD138 expression was found in 60% of all SGC with differing expression across entities (p < 0.01). A mean of 25.2% of the tumor cells in mucoepidermoid carcinoma (MuEp) were positive, followed by epithelial-myoepithelial carcinoma (20.9%), acinic cell carcinoma (16.0%), and SaDu (15.2%). High-/intermediate-grade MuEp showed CD138 expression in a mean of 34.8% of tumor cells. For SaDu, lymph node metastases showed CD138 expression in a mean of 31.2% of tumor cells which correlated with CD138 expression in their primaries (p = 0.01; Spearman's ρ = 0.71). MALDI-MS imaging confirmed the presence of the CD138 protein in SGC. No significant association was found between clinicopathological data, including progression-free survival (p = 0.50) and CD138 expression. CD138 is expressed in the cell membrane of different entities of SGC and SaDu lymph node metastases and therefore represents a potential target for CD138 targeting drugs.

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

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

[Novel therapeutic approaches for salivary gland carcinomas]. / Neue Therapieansätze für Speicheldrüsenmalignome.

Novel therapeutic options for the treatment of salivary gland malignancies have emerged due to the improvement and distribution of molecular pathological testing methods and the availability of targeted therapies. Since they are less toxic, these new agents are a valuable alternative to conventional cytotoxic chemotherapy. On the one hand, there are new entity-specific therapies such as NTRK inhibitor therapy for secretory carcinomas and axitinib therapy for adenoid cystic carcinomas. Moreover, cross-entity therapeutics such as antiandrogenic therapy, HER2 inhibition, and PI3K inhibition are also coming to the fore. For metastatic/recurrent salivary gland carcinomas that cannot be treated with targeted therapy, platinum-based chemotherapies continue to be therapy of choice.

Misleading Morphologic and Phenotypic Features (Transdifferentiation) in Solitary Fibrous Tumor of the Head and Neck: Report of 3 Cases and Review of the Literature.

Solitary fibrous tumor (SFT) is a rare fibroblastic neoplasm with potentially malignant behavior that may develop in any anatomic site and may involve the head and neck (H&N) region as well. Although typical SFT has a relatively characteristic morphology, its morphologic spectrum is extraordinarily broad and also includes rare cases with dedifferentiation or transdifferentiation which result in aberrant morphologic and/or immunohistochemical features. However, since virtually all cases are molecularly characterized by NAB2::STAT6 gene fusions, molecular genetic methods or STAT6 immunohistochemistry can be effectively used in confirming the diagnosis. Herein, we report 3 diagnostically challenging H&N SFT cases with an unusual morphology and/or phenotypes closely mimicking other well-known H&N entities. The tumors originated in the oral minor salivary glands, the base of the tongue, and sinonasal tract and closely resembled hyalinizing clear cell carcinoma of the salivary gland, adenocarcinoma not otherwise specified and biphenotypic sinonasal sarcoma, respectively. All cases were positive for cytokeratins, variably expressed S100 protein, showed diffuse nuclear STAT6 positivity, and harbored NAB2::STAT6 gene fusions.

Mutually Exclusive Expression of COL11A1 by CAFs and Tumour Cells in a Large panCancer and a Salivary Gland Carcinoma Cohort.

Procollagen 11A1 (COL11A1) is a central component of the extracellular matrix in many carcinomas, which is considered to be mainly produced by cancer associated fibroblasts (CAFs). As COL11A1 expression correlates with adverse prognosis and is implicated in chemoresistance, it is a promising putative target. For the first time, we used RNA in-situ hybridization to systematically identify the cells that produce COL11A1 in the ten most prevalent carcinoma types, lymphomas (n = 275) and corresponding normal tissue (n = 55; panCancer cohort). Moreover, as most salivary gland carcinomas (SGC) display distinct stromal architectures, we also analysed 110 SGC. The corresponding protein formation of COL11A1 was determined by MALDI-TOF-MS-Imaging. We report that colon, breast and salivary duct carcinomas are highly infiltrated by COL11A1 positive CAFs (CAFsCOL11A1) and might thus be promising candidates for antidesmoplastic or COL11A1-targeted therapies. The amount of CAFsCOL11A1 correlated significantly with tumour grade, tumour stage and nodal spread in the panCancer cohort. Significant associations between CAFsCOL11A1 and vascular invasion, perineural spread and nodal spread were observed in the SGC cohort. Also, we discovered that tumour cells of intercalated duct derived SGC and CAFs produce COL11A1 in a mutually exclusive manner. Our findings represent a novel mode of extracellular matrix production in carcinomas and could be highly relevant in the future. Our findings elucidate the mode of COL11A1 expression in very different carcinoma types and may aid to categorise tumours in the setting of possible future COL11A1-related therapies.

Comprehensive Analysis of VEGFR2 Expression in HPV-Positive and -Negative OPSCC Reveals Differing VEGFR2 Expression Patterns.

VEGF signaling regulated by the vascular endothelial growth factor receptor 2 (VEGFR2) plays a decisive role in tumor angiogenesis, initiation and progression in several tumors including HNSCC. However, the impact of HPV-status on the expression of VEGFR2 in OPSCC has not yet been investigated, although HPV oncoproteins E6 and E7 induce VEGF-expression. In a series of 56 OPSCC with known HPV-status, VEGFR2 expression patterns were analyzed both in blood vessels from tumor-free and tumor-containing regions and within tumor cells by immunohistochemistry using densitometry. Differences in subcellular colocalization of VEGFR2 with endothelial, tumor and stem cell markers were determined by double-immunofluorescence imaging. Immunohistochemical results were correlated with clinicopathological data. HPV-infection induces significant downregulation of VEGFR2 in cancer cells compared to HPV-negative tumor cells (p = 0.012). However, with respect to blood vessel supply, the intensity of VEGFR2 staining differed only in HPV-positive OPSCC and was upregulated in the blood vessels of tumor-containing regions (p < 0.0001). These results may suggest different routes of VEGFR2 signaling depending on the HPV-status of the OPSCC. While in HPV-positive OPSCC, VEGFR2 might be associated with increased angiogenesis, in HPV-negative tumors, an autocrine loop might regulate tumor cell survival and invasion.

Genomic and Transcriptomic Characteristics of Esophageal Adenocarcinoma.

Esophageal adenocarcinoma (EAC) is a deadly disease with limited options for targeted therapy. With the help of next-generation sequencing studies over the last decade, we gained an understanding of the genomic architecture of EAC. The tumor suppressor gene TP53 is mutated in 70 to 80% of tumors followed by genomic alterations in CDKN2A, KRAS, ERBB2, ARID1A, SMAD4 and a long tail of less frequently mutated genes. EAC is characterized by a high burden of point mutations and genomic rearrangements, resulting in amplifications and deletions of genomic regions. The genomic complexity is likely hampering the efficacy of targeted therapies. Barrett's esophagus (BE), a metaplastic response of the esophagus to gastro-esophageal reflux disease, is the main risk factor for the development of EAC. Almost all EACs are derived from BE. The sequence from BE to EAC provides an opportunity to study the genomic evolution towards EAC. While the overlap of point mutations between BE and EAC within the same patient is, at times, surprisingly low, there is a correlation between the complexity of the genomic copy number profile and the development of EAC. Transcriptomic analyses separated EAC into a basal and a classical subtype, with the basal subtype showing a higher level of resistance to chemotherapy. In this review, we provide an overview of the current knowledge of the genomic and transcriptomic characteristics of EAC and their relevance for the development of the disease and patient care.

Trophoblast Cell Surface Antigen 2 (Trop-2) Protein is Highly Expressed in Salivary Gland Carcinomas and Represents a Potential Therapeutic Target.

Treatment options for unresectable, recurrent or metastatic salivary gland carcinomas (SGC) are scarce. Trophoblast cell surface antigen 2 (Trop-2) is a transmembrane glycoprotein that is involved in a variety of oncogenic cell signaling pathways. Its potential as a target for the antibody-drug conjugate sacituzumab govitecan has already been demonstrated in different tumor entities. The United States Food and Drug Administration approved this antibody-drug conjugate for the treatment of metastatic triple-negative breast cancer. Here, we aimed to investigate Trop-2 protein expression in different entities of SGCs. We retrospectively reviewed the medical records of all patients that underwent surgery for a primary SGC in a tertiary referral center between 1990 and 2014. Immunohistochemical (IHC) staining for Trop-2 was performed and rated as negative, weak, moderate or high using a semiquantitative score. Additionally, representative cases were analyzed using MALDI-mass spectrometry (MS) imaging to confirm the IHC results. The cohort consisted of 114 tumors of the parotid gland (90.4%) and submandibular gland (9.6%). It mainly included mucoepidermoid, salivary duct and adenoid cystic carcinomas. In IHC samples, 44% showed high, 38% moderate and 10% weak expression rates of Trop-2. MALDI-MS imaging confirmed the presence of Trop-2 protein in 80% of the tested tumor samples. This is the first study to demonstrate that several types of SGC express Trop-2 with variable intensity. Since there are currently few systemic treatment options for advanced SGCs, Trop-2 represents a promising target for further clinical studies, for instance, with sacituzumab govitecan.

Survival after parotid gland metastases of cutaneous squamous cell carcinoma of the head and neck.

PURPOSE: Malignant tumours in the parotid gland can originate either from the gland itself or as a result of metastatic spread of other tumours, such as cutaneous squamous cell carcinomas (CSCC) of the head and neck area. The aim of this study was to analyse and compare the clinical behaviour of primary as well as CSCC metastatic parotid cancers with special emphasis on therapy and oncologic outcome. METHODS: Clinical and histopathological data of 342 patients with parotid gland malignomas surgically treated in a tertiary referral centre between 1987 and 2015 were retrospectively assessed. Oncologic outcomes of all cases with CSCC metastasis of the parotid gland (n = 49) were compared to those of primary parotid gland carcinomas (n = 293). RESULTS: Mean age at diagnosis was 72.3 years for CSCC patients versus 56.8 years in patients with primary parotid carcinoma. A total of 83.7% of CSCC patients were male, compared to 48.8% in the group of primary carcinomas. Forty-five out of 49 CSCC patients underwent total parotidectomy and neck dissection (91.8%). A total of 93.9% out of all CSCC patients received adjuvant radiotherapy. Five-year overall survival (OS) was 32.6% in CSCC patients versus 77.2% in primary parotid carcinoma patients. CONCLUSION: As compared to primary parotid cancers, we could show that patients suffering from CSCC metastases to the parotid gland presented with significantly higher age and worse survival.

Expression profiling on subclasses of primary parotid gland carcinomas.

INTRODUCTION: The underlying molecular mechanisms of parotid gland carcinomas (PGC) are still unknown. Knowledge about the tumor-driving signaling pathways is necessary either for diagnostics or developing new therapeutic options in this heterogeneous and rare entity. MATERIAL AND METHODS: 94 matching RNA formalin-fixed and paraffin-embedded tissue samples from PGC and the corresponding non-tumor area, RNA quality and quantity were sufficient for gene expression profiling of 770 genes using the NanoString's nCounter technology. Oncogenic and tumor suppressor genes were examined in the three common PGC tumor entities: adenoid cystic carcinoma (ACC), adenocarcinoma NOS (AC-NOS), and mucoepidermoid carcinoma (MEC). RESULTS: Expression profiling and subsequent hierarchical cluster analysis clearly differentiated between non-tumor gland tissue samples and PGC. In addition expression pattern of all three entities differed. The extensive pathway analysis proved a prominent dysregulation of the Wnt signaling pathway in the three PGC entities. Moreover, transcript upstream analysis demonstrated a pronounced activation of the PI3K pathway in ACC and MEC. DISCUSSION: Our findings revealed divergent molecular expression profiles in MEC, ACC and AC-NOS that are presently studied for their potential application in PGC diagnostics. Importantly, identification of Wnt and PI3K signaling in PGC revealed novel options of PGC therapy.

Expression Profiling of Extracellular Matrix Genes Reveals Global and Entity-Specific Characteristics in Adenoid Cystic, Mucoepidermoid and Salivary Duct Carcinomas.

The composition of the extracellular matrix (ECM) plays a pivotal role in tumour initiation, metastasis and therapy resistance. Until now, the ECM composition of salivary gland carcinomas (SGC) has not been studied. We quantitatively analysed the mRNA of 28 ECM-related genes of 34 adenoid cystic (AdCy; n = 11), mucoepidermoid (MuEp; n = 14) and salivary duct carcinomas (SaDu; n = 9). An incremental overexpression of six collagens (including COL11A1) and four glycoproteins from MuEp and SaDu suggested a common ECM alteration. Conversely, AdCy and MuEp displayed a distinct overexpression of COL27A1 and LAMB3, respectively. Nonhierarchical clustering and principal component analysis revealed a more specific pattern for AdCy with low expression of the common gene signature. In situ studies at the RNA and protein level confirmed these results and indicated that, in contrast to MuEp and SaDu, ECM production in AdCy results from tumour cells and not from cancer-associated fibroblasts (CAFs). Our findings reveal different modes of ECM production leading to common and distinct RNA signatures in SGC. Of note, an overexpression of COL27A1, as in AdCy, has not been linked to any other neoplasm so far. Here, we contribute to the dissection of the ECM composition in SGC and identified a panel of deferentially expressed genes, which could be putative targets for SGC therapy and overcoming therapeutic resistance.