Increased SOX2 expression in salivary gland carcinoma ex pleomorphic adenoma progression: an association with adverse outcome

The Immunoexpression and Prognostic Significance of Stem Cell Markers in Malignant Salivary Gland Tumors: A Systematic Review and Meta-Analysis

Background/Objectives: Salivary gland carcinomas encompass a broad group of malignant lesions characterized by varied prognoses. Stem cells have been associated with the potential for self-renewal and differentiation to various subpopulations, resulting in histopathological variability and diverse biological behavior, features that characterize salivary gland carcinomas. This study aims to provide a thorough systematic review of immunohistochemical studies regarding the expression and prognostic significance of stem cell markers between different malignant salivary gland tumors (MSGTs). Methods: The English literature was searched via the databases MEDLINE/PubMed, EMBASE via OVID, Web of Science, Scopus, and CINHAL via EBSCO. The Joanna Briggs Institute Critical Appraisal Tool was used for risk of bias (RoB) assessment. Meta-analysis was conducted for markers evaluated in the same pair of diseases in at least two studies. Results: Fifty-four studies reported the expression of stem cell markers, e.g., c-KIT, CD44, CD133, CD24, ALDH1, BMI1, SOX2, OCT4, and NANOG, in various MSGTs. Low, moderate, and high RoB was observed in twenty-five, eleven, and eighteen studies, respectively. Meta-analysis revealed an outstanding discriminative ability of c-KIT for adenoid cystic carcinoma (AdCC) over polymorphous adenocarcinoma [P(LG)A] but did not confirm the prognostic significance of stem cell markers in MSGTs. Conclusions: This study indicated a possible link between stem cells and the histopathological heterogeneity and diverse biological behavior that characterize the MSGTs. c-KIT might be of diagnostic value in discriminating between AdCC and P(LG)A.

Molecular Factors in Carcinoma Ex Pleomorphic Adenoma: Systematic Review and Meta-Analysis

OBJECTIVE

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor. Although multiple reviews have been published on salivary gland malignancies, it has been a decade since the last dedicated systematic review pertaining to CXPA alone was published. This study examines molecular factors in CXPA diagnosis.

DATA SOURCES

MEDLINE, CINAHL, Embase, Scopus, Web of Science (BIOSIS), Cochrane CENTRAL, Health Collection (Informit), OpenDOAR, and GreyNet International.

REVIEW METHODS

Systematic review and meta-analysis from inception to October 31, 2022 for all English language studies pertaining to "carcinoma ex pleomorphic adenoma." Predicted incidence of each biomarker was calculated with meta-analysis. Comparison against pleomorphic adenoma (PA) and salivary duct carcinoma (SDC) when reported within the same study are performed. Risk of bias performed with JBI tool for prevalence studies.

RESULTS

Of 19151 unique studies undergoing abstract screening, 55 studies (n = 1322 patients) underwent data analysis. Biomarkers with >3 studies were p53, HER2, AR, EGFR, PLAG1, ERBB, ER, PR, HMGA2, p16, p63, a-SMA, RAS, PTEN, PDL1, BRAF, PIK3CA, and c-kit. Highest incidence was seen in AR, EGFR, p16, and p53. Significant differences were demonstrated compared with PA and SDC. There was high heterogeneity and overall high risk of bias within studies.

CONCLUSION

Molecular factors are an area of interest in the diagnosis of CXPA. Our study results support examining CXPA as a discrete cohort in future targeted therapy trials. Laryngoscope, 134:1042-1053, 2024.

Carcinoma Ex Pleomorphic Adenomas: An Institutional Experience and Literature Review

OBJECTIVES

To provide an institutional experience with cases diagnosed as carcinoma ex pleomorphic adenoma (CXPA), including the cytologic and histologic findings and clinical follow-up, followed by a comparison to the experience documented in the literature.

METHODS

We identified cases of CXPA diagnosed at our institution from 2011 to 2021 and reviewed the cytologic and histologic diagnoses, as well as the treatment and clinical outcomes. Additionally, a literature review of the English literature was performed on CXPAs from 2011 to 2021.

RESULTS

Forty-one cases of CXPA were identified, with the majority subclassified as adenocarcinoma, not otherwise specified. Five tumors underwent cytogenetic studies and five underwent molecular studies. To date, 36 patients are alive, 8 of whom experienced locoregional recurrence or distant metastasis.

CONCLUSIONS

Our institutional experience was comparable to that reported in the literature. Further studies are required to inquire about the role of molecular profiles of CXPAs in clinical risk assessment.

Immunohistochemical comparative analysis of tumor stem cell biomarkers in pleomorphic adenoma, adenoid cystic carcinoma and mucoepidermoid carcinoma of salivary glands

OBJECTIVE

This study aimed to compare the immunoexpression profile of tumor stem cell (TSC) biomarkers CD44, aldehyde dehydrogenase 1 (ALDH1), OCT4, and SOX2 in salivary gland tumors (SGTs).

STUDY DESIGN

Sixty tissue specimens of SGTs, including 20 pleomorphic adenomas, 20 adenoid cystic carcinomas (ACCs), and 20 mucoepidermoid carcinomas, in addition to 4 samples of normal glandular tissue, were subjected to immunohistochemistry. The expression of the biomarkers in the parenchyma and stroma was evaluated. Data were analyzed statistically by nonparametric tests (P < .05).

RESULTS

Higher parenchymal expression of ALDH1, OCT4, and SOX2 was observed in pleomorphic adenomas, ACCs, and mucoepidermoid carcinomas, respectively. Most ACCs did not express ALDH1. Higher immunoexpression of ALDH1 in major SGTs (P = .021) and of OCT4 in minor SGTs (P = .011) was found. Immunoexpression of SOX2 was related to lesions without myoepithelial differentiation (P < .001) and malignant behavior (P = .002). Furthermore, OCT4 was related to myoepithelial differentiation (P = .009). CD44 expression was related to a better prognosis. Stromal immunoexpressions of CD44, ALDH1, and OCT4 were higher in malignant SGTs.

CONCLUSIONS

Our findings suggest the participation of TSCs in the pathogenesis of SGTs. We emphasize the need for further investigations into the presence and role of TSCs in the stroma of these lesions.

Cancer stem cell markers in adenocarcinoma of the salivary glands - reliable prognostic markers?

Purpose

Adenocarcinoma of the salivary glands is of low incidence and a broad range of histopathological subtypes. Cancer stem cell markers (CSC) might serve as novel prognostic parameters. To date, only a few studies examined the expression of CSC in adenocarcinoma of the salivary glands with diverging results. To further investigate the reliability in terms of prognostic value, a histopathological analysis of CSCs on a cohort of patients with adenocarcinomas of the major salivary glands was performed.

Methods

Tumor samples of 40 consecutive patients with adenocarcinoma of the major salivary gland treated with curative intend at one tertiary center were stained with the CSCs ALDH1, BMI-1, CD44, Nanog, and SOX2. Expression of these markers was correlated with clinicopathological parameters and survival estimates.

Results

Correlation of high expression of ALDH1 with higher grading (p < 0.001) and high expression of CD44 with the localization of the neoplasm (p = 0.05), larger tumor size (p = 0.006), positive pN-category (p = 0.023), and advanced UICC stage (p = 0.002) was found. Furthermore, high expression of SOX2 correlated with a negative perineural invasion (p = 0.02). No significant correlation of any investigated marker with survival estimates was observed.

Conclusion

In conclusion, our study did not find a significant correlation of the investigated CSCs with survival estimates in adenocarcinoma of the major salivary glands. Recapitulating the results of our study in conjunction with data in the literature, the CSCs ALDH1, BMI-1, CD44, Nanog, and SOX2 do not seem to serve as reliable prognostic parameters in the treatment of adenocarcinoma of the salivary glands.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06389-7) contains supplementary material, which is available to authorized users.

Gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in carcinoma ex pleomorphic adenoma development

OBJECTIVE

To analyze the gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in normal salivary gland (NSG), pleomorphic adenoma (PA), and carcinoma ex pleomorphic adenoma (CXPA) samples.

MATERIAL AND METHODS

The gene expression was investigated by the real-time PCR (qRT-PCR) method in 9 samples of frozen tissues of normal salivary gland, 13 PA, and 10 CXPA. We validated the reactions by immunohistochemistry on 20 samples from NSG, 85 PA, and 44 CXPA.

RESULTS

Our results showed that there was no statistically significant difference in HIF-1α gene and immunohistochemistry expression among the tissues studied while FASN gene and immunohistochemistry expression increased along the carcinogenesis of the PA. GLUT-1 was significantly more expressed in tumor tissues (PA and CXPA), although protein is mainly expressed in transformed cells than in PA and NSG. In contrast, adipophilin was significantly more expressed in NSG while the expression of the protein increased in PA and CXPA.

CONCLUSIONS

In summary, the data presented here suggest that neoplastic cells reprogram the expression of GLUT-1 and adipophilin to adapt to the tumor microenvironment and reinforce, through immunohistochemical results, a possible transcriptional and post-translational regulatory mechanisms that act on the expression of these genes.

The current markers of cancer stem cell in oral cancers

Head and neck cancer (HNC) constitute 5% of all reported cancers. Among all, the oral cavity cancer is the most frequent type of HNC which accounts for over half of HNC cases. Mouth cancer ranks the sixth leading cause of cancer-related mortality. Generally, conventional chemotherapy has shown success at decreasing relapse and metastasis rates and improves the overall prognosis. Recently, target therapy and targeted drug delivery systems have been introduced as promising treatments. The elimination of efficiency of current therapeutic strategies due to the spared cancer stem cells that cause chemotherapy resistance, relapse and metastasis. Inefficiency methodologies in the elimination of all cancer cells in the body are a major problem that remained to be resolved before to confront the new cancer therapies. Many studies imply to cancer stem cell markers as important agents for targeted anti-cancer as well as improving chemotherapy efficiencies. The potentials of targeted cancer therapy led us to search for novel markers in the mouth cancer stem cells especially in rare cancers. The aimed of this research was, first a comprehensive critical review of the previous studies on the markers of cancer stem cells in oral cancers including oral squamous cell carcinoma, salivary gland cancers, and to highlight the most common cancer stem cell markers which have potential to be exploited as indicators for the preneoplastic lesion malignancy, oral cancer progression, and/or treatment prognosis.

Genes Involved in the Transcriptional Regulation of Pluripotency Are Expressed in Malignant Tumors of the Uterine Cervix and Can Induce Tumorigenic Capacity in a Nontumorigenic Cell Line

Transcription factors OCT4, SOX2, KLF4, C-MYC, and NANOG (OSKM-N) regulate pluripotency and stemness, and their ectopic expression reprograms human and murine fibroblasts that constitute the key of regenerative medicine. To determine their contribution to cell transformation, we analyzed the gene expression profiles of these transcription factors in cervical cancer samples and found that they are preferentially expressed in the tumor component. Also, cancer stem cell-enriched cultures grown as sphere cultures showed overexpression of OSKM-N genes. Importantly, we observed that lentiviral-mediated transduction of these factors confers, to a nontumorigenic immortalized human cell line, properties of cancer stem cells as the ability to form tumors in a mouse model. When we performed a meta-analysis using microarray data from cervical cancer biopsies and normal tissues, we found that the expression of OSKM-N and some target genes allowed separating tumor and normal tissues between samples, which enhanced the importance of OSKM-N in the tumorigenesis. Finally, we analyzed and compared both transcript and protein expression profiles of these factors within a cohort of patients with cervical cancer. To our knowledge, this is the first time that the expression of OSKM-N is described to induce one of the main characteristics of the cancer stem cell, the tumorigenicity. And, more importantly, its exogenous expression in a nontumorigenic cell line is sufficient to induce a tumorigenic phenotype; furthermore, the differential expression of this transcription factor distinguishes tumor tissue and normal tissue in cervical samples.

Salivary gland stem cells: A review of development, regeneration and cancer

Salivary glands are responsible for maintaining the health of the oral cavity and are routinely damaged by therapeutic radiation for head and neck cancer as well as by autoimmune diseases such as Sjögren's syndrome. Regenerative approaches based on the reactivation of endogenous stem cells or the transplant of exogenous stem cells hold substantial promise in restoring the structure and function of these organs to improve patient quality of life. However, these approaches have been hampered by a lack of knowledge on the identity of salivary stem cell populations and their regulators. In this review we discuss our current knowledge on salivary stem cells and their regulators during organ development, homeostasis and regeneration. As increasing evidence in other systems suggests that progenitor cells may be a source of cancer, we also review whether these same salivary stem cells may also be cancer initiating cells.