Investigation of IL-33 serum levels in patients with benign and malignant salivary gland tumors

The clinicopathological implications of serum IL-33 and sST2 as cancer biomarkers: A narrative review

Background

Interleukin (IL)-33 and its receptor, soluble suppression of tumorigenicity 2 (sST2), are key players in the immune response and cancer biology. IL-33 can promote tumorigenesis by enhancing cancer cell proliferation and modulating the immune environment to support tumor growth. Conversely, it can also bolster anti-tumor immunity by recruiting and activating immune effector cells. IL-33 plays a role in multiple aspects of cancer biology, such as promoting immune evasion, tumor growth, and metastasis.

Objective

This study intends to assess the prognostic significance of serum IL-33 and sST2 in cancer and their association with clinicopathologic characteristics (CPC).

Material & methods

Scopus, PubMed electronic databases and other sources were searched and analysed from 2008-2025. The quality of the study was assessed using the Newcastle-Ottawa Quality Assessment Scale.

Results

A total of forty-four studies meeting the inclusion criteria were analyzed. These studies primarily employed an observational and analytical designs, with the majority conducted in the Southeast Asian region, particularly in China. Among the studies investigating serum IL-33 levels in cancer, 68% (26/38) reported elevated serum IL-33 levels, with the majority focusing on hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC), followed by breast (BC) and colon rectal cancer (CRC). Additionally, 85% (22/26) of the reports found a significant association between serum IL-33 expression in cancer and CPC. For regulating the availability and activity of IL-33, sST2, a decoy receptor that binds to IL-33, is crucial. Of the studies assessing sST2 in cancer, 55% (12/22) showed elevated sST2 levels, with most focusing on HCC, followed by BC and CRC. Furthermore, 54% (7/13) of these studies identified a significant correlation between sST2 levels and CPC.

Conclusion

The detection of increased serum IL-33 across various malignancies highlights its potential as an emerging biomarker for cancer detection and prognosis. Similarly, elevated sST2 levels have been observed in different cancers and are linked to poor prognosis, further highlighting its potential as a biomarker for tumor progression. The IL-33/ST2 signaling pathway could offer new cancer treatment strategies by enhancing immune responses while mitigating tumor-promoting effects. This study explores the roles of IL-33 and sST2 as biomarkers, their relevance in cancer diagnostics and therapeutics, and their correlation with clinical outcomes across different cancer types.

The Impact of Inflammation on the Etiopathogenesis of Benign Salivary Gland Tumors: A Scoping Review

Salivary gland tumors are rare head and neck tumors constituting up to 6% of all head and neck neoplasms; despite being mostly benign, these tumors present in diverse histological subtypes, making them challenging to diagnose and treat. Our research aims to investigate the link between inflammation and tumorigenesis within the salivary glands based on the literature regarding the etiopathogenesis of benign salivary gland tumors. This scoping review was conducted following the PRISMA extension for scoping reviews and reporting guidelines. The search was conducted using the Pubmed and Embase databases. Articles published between 2004 and May 2024 were included in the review. A total of 1097 papers were collected and identified. After 271 duplicates were removed, 826 titles and abstracts were independently reviewed by two researchers. Based on the title and abstract, 735 citations were excluded, and 91 articles were assessed for eligibility. Data were extracted from 46 articles that met the inclusion criteria. The review highlights the significance of inflammation-related factors and its relations with benign salivary gland tumors (SGTs). Knowledge of the etiopathogenesis of these tumors remains insufficient, and their rich immunological background poses challenges in diagnosis. The findings also point to directions for further clinical research, which will be necessary to implement these molecules in clinical practice.

Clinical Biomarkers in Otolaryngology-Head and Neck Surgery

OBJECTIVE

The purpose of this paper is to review the literature and compile promising and clinically relevant biomarkers in otolaryngology-head & neck surgery not related to autoimmune disorders.

STUDY DESIGN

Narrative review.

METHODS

PubMed and Google Scholar were queried using combined key words such as "biomarkers" and "otolaryngology." Additional queries were made with combined key words such as "biomarkers" and a particular subspecialty such as "rhinology" or "otology" to maximize yield of relevant titles. Subsequently, specific biomarkers identified, such as "beta-2 transferrin," were used as key words. Relevant titles were reviewed and selected for abstract review. Applicable abstracts were then selected for review of the full text.

RESULTS

Biomarkers currently in clinical use within the field of otolaryngology were included in this review. The compiled biomarkers were then detailed individually regarding their molecular characteristics, function, and clinical significance.

CONCLUSIONS

The number of biomarkers in use in otolaryngology is rapidly expanding representing a new diagnostic modality for our field. This review defines the key biomarkers that are currently or likely to be soon translated into clinical use within the field of otolaryngology. The majority of these biomarkers are in the form of proteins such as beta-2 transferrin, thyroglobulin, and P16. Given their growing impact on diagnosis, management and surveillance of otolaryngologic disorders periodic surveys are needed for education and to guide further advances and applications of otolaryngologic biomarkers.

Biological effects of IL-33/ST2 axis on oral diseases: autoimmune diseases and periodontal diseases

IL-33 is a relatively new member of the IL-1 cytokine family, which plays a unique role in autoimmune diseases, particularly some oral diseases dominated by immune factors. The IL-33/ST2 axis is the main pathway by which IL-33 signals affect downstream cells to produce an inflammatory response or tissue repair. As a newly discovered pro-inflammatory cytokine, IL-33 can participate in the pathogenesis of autoimmune oral diseases such as Sjogren's syndrome and Behcet's disease. Moreover, the IL-33/ST2 axis also recruits and activates mast cells in periodontitis, producing inflammatory chemokines and mediating gingival inflammation and alveolar bone destruction. Interestingly, the high expression of IL-33 in the alveolar bone, which exhibits anti-osteoclast effects under appropriate mechanical loading, also confirms its dual role of destruction and repair in an immune-mediated periodontal environment. This study reviewed the biological effects of IL-33 in autoimmune oral diseases, periodontitis and periodontal bone metabolism, and elaborated its potential role and impact as a disease enhancer or a repair factor.

IL-33 biology in cancer: An update and future perspectives

Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is constitutively expressed in the nucleus of epithelial, endothelial and fibroblast-like cells. Upon cell stress, damage or necrosis, IL-33 is released into the cytoplasm to exert its prime role as an alarmin by binding to its specific receptor moiety, ST2. IL-33 exhibits pleiotropic function in inflammatory diseases and particularly in cancer. IL-33 may play a dual role as both a pro-tumorigenic and anti-tumorigenic cytokine, dependent on tumor and cellular context, expression levels, bioactivity and the nature of the inflammatory environment. In this review, we discuss the differential contribution of IL-33 to malignant or inflammatory conditions, its multifaceted effects on the tumor microenvironment, while providing possible explanations for the discrepant findings described in the literature. Additionally, we examine the emerging and divergent functions of IL-33 in the nucleus, and aspects of IL-33 biology that are currently under-addressed.