Somatostatin receptor 2 is highly sensitive and specific for Epstein-Barr virus-associated nasopharyngeal carcinoma

Top IHC/ISH Hacks for and Molecular Surrogates of Poorly Differentiated Sinonasal Small Round Cell Tumors

BACKGROUND

Poorly differentiated sinonasal small round cell tumors (SRCTs) are rare and heterogeneous, posing challenges in diagnosis and treatment.

METHODS

Recent advances in molecular findings and diagnostic refinement have promoted better understanding and management of these tumors.

RESULTS

The newly defined and emerging sinonasal entities demonstrate diverse morphologies, specific genomic signatures, and clinical behavior from conventional counterparts. In this review of SRCTs, emphasis is placed on the diagnostic approach with the employment of a pertinent panel of immunohistochemistry studies and/or molecular tests, fine-tuned to the latest WHO 5 classification of sinonasal/paranasal tumors and personalized treatment.

CONCLUSION

Specifically, this review focuses on tumors with epithelial and neuroectodermal derivation.

Somatostatin receptor2 (SSTR2) expression, prognostic implications, modifications and potential therapeutic strategies associates with head and neck squamous cell carcinomas

Head and neck squamous cell carcinomas (HNSCC) constitute a heterogeneous cluster of tumors celebrated for their predisposition to metastasize and exhibit local recurrence. Recent explorations have illuminated the intricate involvement of Somatostatin Receptor 2 (SSTR2), a growth-regulatory receptor traditionally classified as a tumor suppressor, yet concurrently implicated in bolstering specific tumor phenotypes. Advances in the realm of SSTR2 investigation within HNSCC, with a specific spotlight on laryngeal squamous cell carcinomas (LSCC), tongue squamous cell carcinomas (TSCC), and nasopharyngeal carcinomas (NPC), have been established. This study aims to provide a comprehensive overview of SSTR2 expression patterns, prognostic implications, distinctive signaling pathways, epigenetic modifications, and potential therapeutic strategies associated with SSTR2 in HNSCC.

SSTR2 positively associates with EGFR and predicts poor prognosis in nasopharyngeal carcinoma

AIMS

Epidermal growth factor receptor (EGFR) belongs to the receptor tyrosine kinases family and overexpression of EGFR has been linked to poor prognosis and cancer progression. Somatostatin receptor 2 (SSTR2) is a G-protein-coupled receptor (GPCR) with diverse biological functions in humans, and it is upregulated through the NF-KB signalling pathway in nasopharyngeal carcinomas (NPC). However, no studies have examined the EGFR and SSTR2 in NPC. This study aimed to investigate whether SSTR2 is associated with EGFR and clinicopathological features in NPC.

METHODS

Bioinformatics analysis was performed to assess the correlation between EGFR and SSTR2 based on the GEO database. The expression of SSTR2 and EGFR was evaluated by immunohistochemistry (IHC) in 491 cases of NPC and 50 cases of non-cancerous nasopharyngeal epithelium.

RESULTS

The bioinformatics analysis and IHC showed a positive correlation between SSTR2 and EGFR in NPC. High expression of SSTR2 and EGFR was significantly increased in NPC patients compared with non-cancerous nasopharyngeal epithelium. High expression of SSTR2 and/or EGFR was associated with a worse outcome and a higher risk of progression. The study found that patients receiving chemoradiotherapy (CR) with high expression of SSTR2, high expression of EGFR, and high coexpression of SSTR2 and EGFR had a poorer prognosis in both progression-free survival (PFS) and overall survival (OS). Interestingly, NPC patients with high expression of SSTR2, high expression of EGFR, high coexpression of EGFR and SSTR2, and EGFR/SSTR2 anyone high expression had a better prognosis with CR combined with targeted therapy. Cox multivariate analysis identified SSTR2 and EGFR as independent poor predictors of PFS.

CONCLUSION

Our study is the first to shed light on the intricate relationship between SSTR2 and EGFR in NPC and provides new insights into the potential benefits of EGFR targeted therapy for patients with high SSTR2 expression. Additionally, SSTR2 has potential as a new biomarker for poor prognosis in NPC patients.

Therapeutic strategy for oncovirus-mediated oral cancer: A comprehensive review

Oral cancer is a neoplastic disorder of the oral cavities, including the lips, tongue, buccal mucosa, and lower and upper gums. Oral cancer assessment entails a multistep process that requires deep knowledge of the molecular networks involved in its progression and development. Preventive measures including public awareness of risk factors and improving public behaviors are necessary, and screening techniques should be encouraged to enable early detection of malignant lesions. Herpes simplex virus (HSV), human papillomavirus (HPV), Epstein-Barr virus (EBV), and Kaposi sarcoma-associated herpesvirus (KSHV) are associated with other premalignant and carcinogenic conditions leading to oral cancer. Oncogenic viruses induce chromosomal rearrangements; activate signal transduction pathways via growth factor receptors, cytoplasmic protein kinases, and DNA binding transcription factors; modulate cell cycle proteins, and inhibit apoptotic pathways. In this review, we present an up-to-date overview on the use of nanomaterials for regulating viral proteins and oral cancer as well as the role of phytocompounds on oral cancer. The targets linking oncoviral proteins and oral carcinogenesis were also discussed.

Novel Discovery of the Somatostatin Receptor (SSTR2) in Pleomorphic Adenomas via Immunohistochemical Analysis of Tumors of the Salivary Glands

Reliable preoperative diagnosis between salivary gland tumor entities is difficult. In this monocentric retrospective study, we examined the somatostatin receptor 2 (SSTR2) status of salivary gland tumors after salivary gland tumor resection via immunohistochemistry (IHC), and stains were compared in analogy to the HER2 mamma scale. A total of 42.3% of all pleomorphic adenoma (PA) tumors (42 of 99, 95% confidence interval 32.5-52.8%) demonstrated ≥20% of cells displaying the SSTR2 as compared to just 1% of all other tumors (1/160, 95% CI 0.02-3.4%). The other tumor was a neuroendocrine carcinoma. PA had a higher intensity of SSTR2 staining, with 90.9% staining ≥ an intensity of 2 (moderate). Tumors with an intensity of SSTR2 expression equal to or greater than 2 had an 89.9% likelihood of being a PA (95% CI: 82.2-95.0%, AUC: 0.928). Only one Warthin tumor demonstrated a 'strong' SSTR2 staining intensity. No Warthin tumor showed a percentage of cells staining for SSTR2 above ≥20%. This result demonstrates consistent and strong expression of SSTR2 in PAs as compared to Warthin tumors, which may allow physicians to utilize radioligand-somatostatin analog PET CT/MR imaging to diagnose the PA. SSTR2 positivity, if shown to be clinically relevant, may allow peptide receptor radionuclide therapy in the future.

Evolving landscape of PD-L2: bring new light to checkpoint immunotherapy

Immune checkpoint blockade therapy targeting programmed cell death protein 1 (PD-1) has revolutionized the landscape of multiple human cancer types, including head and neck squamous carcinoma (HNSCC). Programmed death ligand-2 (PD-L2), a PD-1 ligand, mediates cancer cell immune escape (or tolerance independent of PD-L1) and predicts poor prognosis of patients with HNSCC. Therefore, an in-depth understanding of the regulatory process of PD-L2 expression may stratify patients with HNSCC to benefit from anti-PD-1 immunotherapy. In this review, we summarised the PD-L2 expression and its immune-dependent and independent functions in HNSCC and other solid tumours. We focused on recent findings on the mechanisms that regulate PD-L2 at the genomic, transcriptional, post-transcriptional, translational, and post-translational levels, also in intercellular communication of tumour microenvironment (TME). We also discussed the prospects of using small molecular agents indirectly targeting PD-L2 in cancer therapy. These findings may provide a notable avenue in developing novel and effective PD-L2-targeted therapeutic strategies for immune combination therapy and uncovering biomarkers that improve the clinical efficacy of anti-PD-1 therapies.

Advances in nuclear medicine-based molecular imaging in head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are often aggressive, making advanced disease very difficult to treat using contemporary modalities, such as surgery, radiation therapy, and chemotherapy. However, targeted therapy, e.g., cetuximab, an epidermal growth factor receptor inhibitor, has demonstrated survival benefit in HNSCC patients with locoregional failure or distant metastasis. Molecular imaging aims at various biomarkers used in targeted therapy, and nuclear medicine-based molecular imaging is a real-time and non-invasive modality with the potential to identify tumor in an earlier and more treatable stage, before anatomic-based imaging reveals diseases. The objective of this comprehensive review is to summarize recent advances in nuclear medicine-based molecular imaging for HNSCC focusing on several commonly radiolabeled biomarkers. The preclinical and clinical applications of these candidate imaging strategies are divided into three categories: those targeting tumor cells, tumor microenvironment, and tumor angiogenesis. This review endeavors to expand the knowledge of molecular biology of HNSCC and help realizing diagnostic potential of molecular imaging in clinical nuclear medicine.

Correlation of Somatostatin Receptor 2 Expression, 68Ga-DOTATATE PET Scan and Octreotide Treatment in Thymic Epithelial Tumors

Somatostatin receptor 2 (SSTR2) has been shown to be expressed in a subset of neuroendocrine tumors and carcinomas and plays a role in imaging studies and guiding therapy. Patients with tumors expressing SSTR2 may be successfully treated with somatostatin inhibitors or radiolabeled somatostatin analogues. We studied SSTR2 expression in TET and correlated it with 68Ga-DOTATATE PET/CT or 68Ga-DOTATATE PET/MR results and treatment outcome. An institutional database of TET was searched for thymoma, thymic carcinoma, and thymic neuroendocrine tumor (TNET) with available resection specimens. Cases were subtyped (2021 WHO classification) and staged (8^th AJCC/UICC staging). A section was stained with anti-SSTR2 antibody (clone UMB1). Percent tumor cells with membranous staining was recorded if present in ≥1% of tumor cells. Medical records were searched for 68Ga-DOTATATE PET scans and treatment. Statistical analysis was performed. Eighty patients (1969-2021) with a median age of 61.3 years (range, 19.1-87.3) (37 males, 46.3%) had thymic carcinoma (N=33), TNET (N=7), or thymoma (N=40). SSTR2 expression was identified in 29 (of 80, 36.3%) TET including 2/2 (100%) small cell carcinomas, 2/5 (40.0%) atypical carcinoid tumors, 16/23 (69.6%) squamous cell carcinomas, 2/2 (100%) lymphoepithelial carcinomas, 1/1 (100%) adenosquamous carcinoma, and 6/40 (15.0%) thymomas. SSTR2 expression in ≥50% of tumor cells (vs 1-49%) was associated with younger age (p=0.023) and shorter recurrence/metastasis-free survival (p=0.007). 68Ga-DOTATATE PET scans (N=9) revealed a Krenning score of 3 in patients with atypical carcinoid tumor, small cell carcinoma, and squamous cell carcinoma (N=1 each) with SSTR2 expression in 95, 100, and 5% of tumor cells, respectively. Scans with Krenning scores of ≤2 (N=5) were seen in tumors with no SSTR2 expression in 80% of cases and a single atypical carcinoid tumor with SSTR2 expression in 10% of tumor cells. One scan resulted as "increased uptake" was in a patient with no SSTR2 expression. In conclusion, 68Ga-DOTATATE PET scans correlated with SSTR2 expression in TET in most patients and appeared to be useful to identify patients with TET who may be amenable to treatment with somatostatin analogues. Larger studies including more patients with 68Ga-DOTATATE PET scans are necessary to independently and prospectively validate our findings.

SSTR2 in Nasopharyngeal Carcinoma: Relationship with Latent EBV Infection and Potential as a Therapeutic Target

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor, most commonly located in the pharyngeal recess and endemic to parts of Asia. It is often detected at a late stage which is associated with poor prognosis (5-year survival rate of 63%). Treatment for this malignancy relies predominantly on radiotherapy and/or systemic chemotherapy, which can be associated with significant morbidity and impaired quality of life. In endemic regions NPC is associated with infection by Epstein-Barr virus (EBV) which was shown to upregulate the somatostatin receptor 2 (SSTR2) cell surface receptor. With recent advances in molecular techniques allowing for an improved understanding of the molecular aetiology of this disease and its relation to SSTR2 expression, we provide a comprehensive and up-to-date overview of this disease and highlight the emergence of SSTR2 as a key tumor biomarker and promising target for imaging and therapy.