DNA mismatch repair system expression in salivary gland tumors: A Systematic Review.

BACKGROUND: The DNA mismatch repair (MMR) system serves as a sophisticated guardian of the precise functioning of the human genome. Dysregulation within this system is linked to the oncogenesis process. Reduced expression of MMR system proteins identified in salivary gland tumors (SGTs) suggests an increased risk of tumoral occurrence. This study aims to analyze the expression of MMR proteins in SGTs and discuss the relevance of this association to the development of these neoplasms. MATERIAL AND METHODS: This review was conducted following the PRISMA guidelines and was registered in PROSPERO (CRD42023465590). A comprehensive search of the PubMed/MEDLINE, Web of Science, Scopus, Embase, and ProQuest (non-peer reviewed platform) was performed to answer the question "Do DNA MMR system proteins exhibit expression in SGTs?". The methodological quality of the selected studies was assessed using the JBI's Critical Appraisal Tool. RESULTS: A total of 142 patients with benign SGTs and 84 with malignant SGTs were included in this review. The literature analysis showed a notable reduction in the expression of DNA MMR system proteins (hHMS2, hMLH1, hMSH3 and hMSH6) in the percentage of marked cells. CONCLUSIONS: The reduction in the expression of the DNA MMR system proteins suggests an interesting correlation with the development of malignant and benign SGTs. Nevertheless, further investigations are warranted to better clarify the precision of measuring biomarker protein expression.

Is epithelial-mesenchymal transition related to the biological behavior of salivary gland neoplasms?

OBJECTIVE: To evaluate and compare the expression of E-cadherin, Snail1 and Twist1 in pleomorphic adenomas (PAs), adenoid cystic carcinomas (AdCCa) and carcinoma ex-pleomorphic adenomas (CaexPA) of salivary glands, as well as investigate possible associations with clinicopathological parameters. STUDY DESIGN: E-cadherin, Snail1 and Twist1 antibody immunostaining were analyzed semiquantitatively in 20 PAs, 20 AdCCas and 10 CaexPAs. Cases were classified as low and high expression for analysis of the association with clinicopathological parameters. RESULTS: Compared to PAs, AdCCas and CaexPAs exhibited higher nuclear expression of Snail1 (p = 0.021 and p = 0.028, respectively) and Twist1 (p = 0.009 and p = 0.001). Membranous and cytoplasmic expression of E-cadherin were positively correlated in PAs, AdCCas and CaexPAs (r = 0.645, p = 0.002; r = 0.824, p < 0.001; r = 0.677, p = 0.031). In PAs, positive correlation was found between nuclear expression of Snail1 and membrane expression of E-cadherin (r = 0.634; p = 0.003), as well as between nuclear expression of Snail1 and Twist1 (r = 0.580; p = 0.007). Negative correlations were detected between membrane expression of E-cadherin and cytoplasmic expression of Snail1 in AdCCas (r = - 0.489; p = 0.029). CONCLUSIONS: E-cadherin, Twist1, and Snail1 may participate in modulating events related to cell differentiation and adhesion in PAs and to biological behavior in AdCCas and CaexPAs, which indicates the involvement of EMT in these processes. Furthermore, the expression of these proteins in these carcinomas may reflect the plasticity feature of EMT.

TGFß signaling pathway in salivary gland tumors.

OBJECTIVE: Pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (ACC) are the most prevalent salivary gland tumors. Their pathogenesis has been recently associated with complex molecular cascades, including the TGFß signaling pathway. The aim of this study was to evaluate the expression of genes associated with the TGFß signaling pathway (TGFB1, ITGB6, SMAD2, SMAD4, FBN1, LTBP1, and c-MYC) to map possible downstream alterations in the TGFß cascade. DESIGN: Thirteen PA, 17 MEC, 13 ACC, and 10 non-neoplastic salivary gland samples were analyzed by real-time RT-PCR. RESULTS: Cases of PA presented increased TGFB1, LTPB1, c-MYC, and FBN1 expressions, whereas SMAD2 expression was decreased when compared to non-neoplastic tissue. MEC patients displayed increased expressions of TGFB1, ITGB6, FBN1, and c-MYC and decreased expressions of SMAD2 and SMAD4. ACC cases exhibited elevated expressions of the investigated genes except TGFB1. The present results suggest that decreased expression of SMAD2 and SMAD4 does not impede the transcriptional regulation of c-MYC, especially in PA and MEC. Increased expressions of ITGB6, TGFB1, LTBP1, and FBN1 appear to be related to the regulation of the TGFß signaling pathway in these tumors. Additionally, we observed a higher expression of SMAD4 in ACC and a raised expression of ITGB6 and lowered expression of SMAD2 in MEC. CONCLUSIONS: Our study demonstrated the differential expression of TGFß cascade members in salivary gland tumors such as SMAD2/SMAD4 and c-MYC as well as the participation of ITGB6, TGFB1, LTBP1, and FBN1, contributing to the understanding of the mechanisms involved in tumor progression.

Identification of MicroRNA Expression Profiles Related to the Aggressiveness of Salivary Gland Adenoid Cystic Carcinomas.

Adenoid cystic carcinoma (ACC) has been reported as the second most common carcinoma of the salivary glands. Few studies have associated miRNA expression with ACC aggressiveness. In this study, we evaluated the miRNA profile of formalin-fixed, paraffin-embedded (FFPE) samples of salivary gland ACC patients using the NanoString platform. We studied the miRNA expression levels associated with the solid growth pattern, the more aggressive histologic feature of ACCs, compared with the tubular and cribriform growth patterns. Moreover, the perineural invasion status, a common clinicopathological feature of the disease that is frequently associated with the clinical progression of ACC, was investigated. The miRNAs showing significant differences between the study groups were selected for target prediction and functional enrichment, which included associations with the disease according to dedicated databases. We observed decreased expression of miR-181d, miR-23b, miR-455, miR-154-5p, and miR-409 in the solid growth pattern compared with tubular and cribriform growth patterns. In contrast, miR-29c, miR-140, miR-195, miR-24, miR-143, and miR-21 were overexpressed in patients with perineural invasion. Several target genes of the miRNAs identified have been associated with molecular processes involved in cell proliferation, apoptosis, and tumor progression. Together, these findings allowed the characterization of miRNAs potentially associated with aggressiveness in salivary gland adenoid cystic carcinoma. Our results highlight important new miRNA expression profiles involved in ACC carcinogenesis that could be associated with the aggressive behavior of this tumor type.

Induction of perineural invasion in salivary adenoid cystic carcinoma by circular RNA RNF111.

OBJECTIVE: Local recurrence, distant metastasis, and perineural invasion (PNI) viciously occur in salivary adenoid cystic carcinoma (SACC), resulting in a poor prognosis. This study aimed to explore the mechanism by which circular RNA RNF111 (circ-RNF111) regulates PNI in SACC by targeting the miR-361-5p/high mobility group box 2 (HMGB2) axis. METHOD: Circ-RNF111 and HMGB2 were highly expressed in SACC specimens, while miR-361-5p was underexpressed. Functional experiments showed that ablating circ-RNF111 or promoting miR-361-5p hindered the biological functions and PNI of SACC-LM cells. RESULTS: HMGB2 overexpression induced the reversal of SACC-LM cell biological functions and PNI caused by circ-RNF111 knockout. Furthermore, reduction of circ-RNF111 suppressed PNI in a SACC xenograft model. Circ-RNF111 regulated HMGB2 expression through targeted modulation of miR-361-5p. CONCLUSION: Taken together, circ-RNF111 stimulates PNI in SACC by miR-361-5p/HMGB2 axis and may serve as a potential therapeutic target for SACC.

Immunohistochemical Expression of Fatty Acid Synthase (FASN) is Correlated to Tumor Aggressiveness and Cellular Differentiation in Salivary Gland Carcinomas.

Fatty acid synthase (FASN) expression is closely related to cancer progression, in particular, tumor aggressiveness and poor prognosis. This study aimed to analyse the expression of FASN in carcinomas of the salivary glands and correlate it with Ki-67 expression. We analysed by immunohistochemistry the expression of FASN and Ki-67 on tissue sections from 7 cases of adenocarcinoma, not otherwise specified (AdNOS), 6 cases of polymorphous adenocarcinoma (PAC), 16 cases of acinic cell carcinoma (AcCC), 19 cases of adenoid cystic carcinoma (AdCC), 15 cases of epithelial-myoepithelial carcinoma (EMC); 10 cases of secretory carcinoma (SC), 13 cases of mucoepidermoid carcinoma (MEC), 10 cases of salivary duct carcinoma (SDC) and 7 cases of myoepithelial carcinoma (MC). These carcinomas were classified into aggressive and indolent regarding their biological behaviour. Additionally, MEC and AdCC were also classified according to the histological grade. High expression of FASN was found in SDC (100%), SC (100%), AcCC (68.7%) and AdNOS (57.2%). No association was found between FASN and Ki-67 expression. Aggressive carcinomas showed a higher rate of Ki-67 proliferation (p < 0.001) and greater expression of FASN when compared to indolent carcinomas (p < 0.05). With regards to carcinomas categorized as indolent, FASN expression was much higher in the lesions that presented cell differentiation (SC and AcCC). Also, FASN expression was significantly higher in high-grade AdCC and MEC when compared to low-grade tumors (p < 0.05). We concluded that FASN expression was correlated to tumor aggressiveness and cellular differentiation in salivary gland carcinomas.

Secretory carcinoma of salivary glands at the National Cancer Institute: A 20-year retrospective clinical, pathological, immunohistochemical and molecular study.

OBJECTIVES: This study aim was to review cases of acinic cell carcinoma (the main differential diagnosis of secretory carcinoma) that were diagnosed and treated at the National Cancer Institute of Brazil (INCA) between 1996 and 2016. The primary objective was to identify underdiagnosed cases of secretory carcinoma via a clinical, immunopathological and molecular reassessment. MATERIALS AND METHODS: This is a cross sectional study, with retrospective data collection from medical records and histological specimen review, with staining for periodic acid-Schiff (PAS) and PAS with diastase, immunohistochemistry for S-100, mammaglobin, and DOG-1, and droplet digital RT-PCR for ETV6-NTRK3. The Research Ethics Committee approved this study, and the patients allowed their participation through informed consent. RESULTS: Eighty-three cases of acinic cell carcinoma were diagnosed and treated in the specified period at INCA, of which, seven had their diagnosis changed to secretory carcinoma. CONCLUSION: The present study adds seven cases of secretory carcinoma to the literature, contributing to a better understanding of the epidemiological, histological, immunohistochemical and molecular characteristics of this recently described tumor. Also, the use of a comprehensive diagnostic approach, including immunohistochemical and molecular methods, along with classical morphological studies, allowed the reclassification of acinic cell carcinoma to secretory carcinoma.

Role of hypoxia-related proteins in adenoid cystic carcinoma invasion.

BACKGROUND: Among cancers affecting the oral cavity, adenoid cystic carcinoma (ACC) is a relatively common malignant neoplasm. It has high rates of metastasis and recurrence and is associated with significant morbidity. During the progression of ACC, the oxygen concentration is reduced in specific areas of the tumour microenvironment, leading to intratumoural hypoxia. The expression of NOTCH1, a disintegrin and metalloproteinase 12 (ADAM-12), hypoxia-inducible factor 1 alpha (HIF-1α), and heparin-binding epidermal growth factor (HB-EGF) under hypoxic conditions has been implicated in invadopodia formation, tumour invasiveness, and metastasis. The aim of this study was to analyse the expression of these proteins to elucidate the mechanisms underlying ACC invasiveness. METHODS: Fifteen ACC samples and 10 normal-looking salivary gland (SG) samples were used to investigate the expression of these proteins by immunohistochemistry. Primary antibodies against NOTCH1, ADAM-12, HIF-1α, and HB-EGF were used. RESULTS: The immunoexpression of all proteins was higher in ACC samples than in SG samples (p < 0.05). CONCLUSIONS: There was increased expression of proteins associated with hypoxia and tumour invasiveness in ACC samples, which indicates a possible role of these proteins in the biological behaviour of this tumour.

Aquaporin 1, 3, and 5 Patterns in Salivary Gland Mucoepidermoid Carcinoma: Expression in Surgical Specimens and an In Vitro Pilot Study.

Salivary gland aquaporins (AQPs) are essential for the control of saliva production and maintenance of glandular structure. However, little is known of their role in salivary gland neoplasia. Salivary gland tumors comprise a heterogeneous group of lesions, featuring variable histological characteristics and diverse clinical behaviors. Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. The aim of this study was to evaluate the expression of AQP1, AQP3, and AQP5 in 24 MEC samples by immunohistochemistry. AQP1 expression was observed in vascular endothelium throughout the tumor stroma. AQP3 was expressed in epidermoid and mucosal cells and AQP5 was expressed in mucosal cells of MEC. These proteins were expressed in the human MEC cell line UH-HMC-3A. Cellular ultrastructural aspects were analyzed by electron microscopy to certificate the tumor cell phenotype. In summary, our results show that, despite the fact that these molecules are important for salivary gland physiology, they may not play a distinct role in tumorigenesis in MEC. Additionally, the in vitro model may offer new possibilities to further investigate mechanisms of these molecules in tumor biology and their real significance in prognosis and possible target therapies.

High levels of ANXA2 are characteristic of malignant salivary gland tumors.

OBJECTIVE: Malignant salivary gland tumors (MSGTs) present different phenotypic characteristics and various clinical outcomes, which proved to be a diagnostic challenge. Considering the heterogeneity of MSGT, this study aims to identify molecule related to the nature of MSGT. METHODS: For screening, proteomic analysis comparing MSGT with pleomorphic adenoma (PA) and salivary gland was performed. The MSGT-associated protein which presented in the higher number in the Gene Expression Omnibus (GEO) database was selected. To validate the data, immunohistochemistry (IHC) was performed in 14 patients with PA, 22 patients with MSGT, and 14 controls. RESULTS: 16 proteins were associated with MSGT. ANXA2 was the primary protein, according to GEO database analyses. ANXA2 was most expressed in the cell membrane. However, some ANXA2 staining was also observed in the cytoplasm and nucleus. ANXA2 was highly expressed in MSGT in comparison with control. Also, ANXA2 has a higher expression in adenocarcinoma not otherwise specified (ANOS) and myoepithelial carcinoma (MC) in comparison with PA. CONCLUSION: In conclusion, this study demonstrated that MSGT presented higher levels of ANXA2 in comparison with normal salivary glands. Also, ANXA2 might be interesting as a molecular marker of ANOS and MS.

Apoptotic signaling in salivary mucoepidermoid carcinoma.

BACKGROUND: Mucoepidermoid carcinoma is the most common malignant tumor of salivary glands. Apoptosis plays an important role in organogenesis of glandular structures, and aberrations of apoptotic mechanisms is associated with a wide array of pathologic conditions. METHODS: The immunoexpression of proteins associated with apoptosis and proliferation was evaluated in 40 mucoepidermoid carcinoma cases. RESULTS: Par-4, Survivin, MUC1, PHLDA1, Fas, and Ki-67 were predominantly expressed in mucoepidermoid carcinoma. FasL was rarely expressed, and Caspase-3 expression was observed in almost 50% of the cases. SPARC expression was associated with low-grade tumors, and Ki-67 expression was associated with lymph node metastasis. Expression of Fas and decreased expression of Ki-67 and Caspase-3 were associated with better overall cancer-specific survival rates. CONCLUSIONS: The association of SPARC and Ki-67 expression with pathological features and the association of Fas, Caspase-3, and Ki-67 with survival probabilities suggest that these proteins may be useful prognostic markers for mucoepidermoid carcinoma.

Is HIF1-a deregulated in malignant salivary neoplasms?

BACKGROUND: There is significant controversy in the literature regarding the relationship between hypoxia and salivary gland neoplasms (SGNs). OBJECTIVE: The current study aims to investigate levels of hypoxia markers in both benign and malignant salivary neoplasms. PATIENTS AND METHODS: The current study sample is comprised of a total of 62 samples. HIF-1α expression was evaluated by immunohistochemistry. Additionally, HIF-1α mRNA and miR-210 levels were assessed using qRT-PCR. RESULTS: No differences in HIF-1α expression were observed among the control group, benign and malignant SGNs. Similarly, HIF-1α mRNA levels were similar between benign and malignant SGNs. Also, there was no difference in miR-210 expression between case and control groups. CONCLUSION: The angiogenic markers, miR-210 and HIF-1α, do not appear to distinguish malignancy in salivary glands.

Salivary gland tumors: Molecular characterization and therapeutic advances for metastatic disease.

Salivary gland cancers represent a rare group of tumors composed by over 20 histological subtypes. Initially treated as one single disease, its diagnosis, prognosis, and treatment are currently being stratified based on morphology. More recently, insight has been provided on the molecular characterization of each subtype, further improving diagnostic accuracy and paving the way for personalized therapy. In this article, we provide a comprehensive review of recent breakthroughs, preliminary results of novel therapy, and future directions on the treatment of these complex malignancies.

Expression of matrix metalloproteinases (MMPs-2, -7, -9, and -26) and tissue inhibitors of metalloproteinases (TIMPs-1 and -2) in pleomorphic adenomas and adenoid cystic carcinomas.

PURPOSE: To compare the immunohistochemical expression of matrix metalloproteinases-2, -7, -9 and -26 and tissue inhibitors of metalloproteinases-1 and -2 in pleomorphic adenomas and adenoid cystic carcinomas of the minor salivary glands. METHODS: Twenty cases of pleomorphic adenomas and 20 cases of adenoid cystic carcinomas were evaluated for the immunohistochemical expression of matrix metalloproteinases-2, -7, -9, and -26 and tissue inhibitors-1 and -2 in tumor parenchyma. RESULTS: Most pleomorphic adenomas and adenoid cystic carcinomas showed high expression of matrix metalloproteinases and tissue inhibitors, predominantly located in the tumor cells. There was no statistically significant difference in the expression of the metalloproteinases-2 (p = 0.359), -7 (p = 0.081), and -26 (p = 0 553), as well as the tissue inhibitors-1 (p = 0.657), and -2 (p = 0.248) between the parenchyma of the studied tumors. Only matrix metalloproteinase-9 showed a significant difference in expression between the two tumors, with adenoid cystic carcinoma showing a more intense staining for this gelatinase (p = 0.041). CONCLUSIONS: The expression of the studied metalloproteinases suggests the involvement of these enzymes in the tissue remodeling process in pleomorphic adenomas and adenoid cystic carcinomas, but only MMP-9, significantly expressed in the adenoid cystic carcinomas, appears to be involved in the process of invasiveness and more aggressive behavior of these tumors. Additionally, results point that TIMPs-1 and -2 may have more complex functions besides metalloproteinase inhibition, which may be related to the pathogenesis and biological behavior of salivary gland tumors.

Abnormal activation of the Akt signaling pathway in adenoid cystic carcinoma.

PURPOSE: Adenoid cystic carcinoma (ACC) is an intriguing lesion because it shows a slow growth in the beginning, but a late poor prognosis due to perineural invasion, metastasis and recurrence. This study aimed to investigate whether Akt signaling would be deregulated in adenoid cystic carcinoma and its consequence in the expression of associated proteins. METHODS: The expression of the Akt, p-Akt, NFκB, ß-catenin, cyclin D1 and COX-2 was assessed by immunohistochemistry in 10 cases of ACC, 17 cases of pleomorphic adenoma (PA), and 7 cases of normal salivary gland (NSG). RESULTS: p-Akt was overexpressed in ACC when compared to NSG. NFκB, ß-catenin, and COX-2 were overexpressed in ACC and PA when compared to NSG. Most proteins were slightly higher expressed in ACC than in PA, but they never reached significance. p-Akt expression positively correlated with NFκB, ß-catenin, cyclin D1 and COX-2 in ACC and PA, while this correlation trended to be negative in for these proteins (except for NFκB) in NSG using Person's correlation analysis, but without reaching significance. CONCLUSIONS: Our results indicate an abnormal activation of Akt signaling pathway, which can be an important regulator of tumor biology in ACC. Activated Akt correlated with the expression of NFκB, ß-catenin and COX-2, which can potentially influence cell survival in ACC.

Differential expression of cyclooxygenase-2 and cyclin D1 in salivary gland tumors.

PURPOSE: Salivary gland tumors are complex and have a great histomorphological diversity; more than 30 histological subtypes are currently described and the study of proteins that help understand and differentiate these tumors is essential. We aimed to analyze the immunoexpression of cyclooxygenase-2 (COX-2) and cyclin D1 proteins in pleomorphic adenomas (PA), mucoepidermoid carcinomas (MEC) and adenoid cystic carcinomas (AdCC) of salivary glands. METHODS: A total of 38 PA, 12 AdCC and 12 MEC underwent immunohistochemical study by the polymeric biotin-free technique. Immunopositive cells were analyzed semi-quantitatively. For statistical analysis, a significance level was set at p ≤ 0.05. RESULTS: Overall, these tumors were more prevalent in women (n = 37). The mean age of these patients was 58-year-old and the parotid gland was the most affected anatomic site (n = 33). All cases of AdCC and MEC showed immunopositivity to cyclin D1; however, 39.5% of the PAs were negative (p < 0.001). Regarding COX-2 immunoexpression, we observed that all cases of CME were positive, whereas 60.5% of the PA and 75% of the CAC analyzed were completely negative (p = 0.042). CONCLUSIONS: The overexpression of COX-2, observed only in MEC, emphasizes that salivary gland tumors have different profiles. Cyclin D1 is more immunoexpressed in malignant tumors. Together, these immunohistochemical findings may be useful in differentiating the studied tumors.

Cripto-1 is overexpressed in carcinoma ex pleomorphic adenoma of salivary gland.

INTRODUCTION: Cripto-1 is a member of the epidermal growth factor-Cripto-1/FRL-1/Cryptic family. Besides being critical for early embryonic development, Cripto-1 is also associated with the development and behavior of several cancers. OBJECTIVE: We analyzed the immunoexpression of Cripto-1 in normal salivary glands (NSGs), pleomorphic adenomas (PAs), and carcinoma ex pleomorphic adenomas (CaExPAs) of salivary glands. METHODS: A total of 12 NSGs, 16 PAs and 12 CaExPAs underwent immunohistochemical study by the polymeric biotin-free technique. Immunopositive cells were evaluated semiquantitatively (scores 0-3). For statistical analysis, Mann-Whitney and Kruskal-Wallis tests were performed and a significance level of p ≤ 0.05 was established. RESULTS: Most CaExPAs (n = 10) were strong positive (score 3) for Cripto-1, and only three cases of PAs and two specimens of NSGs exhibited some expression (score 1), being statistically significant these findings (p < 0.001). No difference between the expression of this protein in tumors of major and minor salivary glands was observed. Overexpression was found mainly in cases of CaExPAs with invasive growth (n = 8) when compared to those without capsular invasion (intracapsular pattern) (p = 0.036). Patients with or without lymph node metastasis showed no difference (p = 0.294). CONCLUSION: The results revealed a significantly higher expression of Cripto-1 in CaExPA compared to PA and NSG, suggesting this protein is possibly deregulated in PA malignant transformation. Furthermore, the increased expression of this protein is associated with a more aggressive behavior (invasive growth) in salivary gland tumors.

Assessment of CTNNB1 gene mutations and ß-catenin immunoexpression in salivary gland pleomorphic adenomas and adenoid cystic carcinomas.

ß-Catenin exerts multiple functions in several neoplasms, playing a major role in cell signaling and tumor progression. This study analyzed possible CTNNB1 mutations in salivary gland pleomorphic adenomas (PAs) and adenoid cystic carcinomas (ACCs), and determined possible differences in ß-catenin immunoexpression in relation to these mutations, as well as histopathological aspects of these tumors. Twenty-four PAs (15 cell-rich and 9 cell-poor tumors) and 24 ACCs (10 tubular, 8 cribriform, and 6 solid tumors) were selected for the analysis of ß-catenin distribution and cellular localization. Furthermore, ß-catenin expression was evaluated using the H-score scoring system. Mutations in CTNNB1 exon 3 were investigated by the single-strand conformational polymorphism test. Diffuse ß-catenin expression was more frequently observed in ACCs compared to PAs (P = 0.008). No significant difference in ß-catenin cellular localization was observed between these tumors (P = 0.098). Comparisons between PA and ACC cases revealed a higher median H-score in the latter (P = 0.036). Cell-rich PAs exhibited a trend for higher H-score than cell-poor tumors (P = 0.060), whereas lower H-scores were observed in cribriform ACCs when compared to tubular and solid ACCs (P = 0.042). Mutations in CTNNB1 were observed in 6 PAs and 7 ACCs, with no significant difference in H-scores for ß-catenin according to mutation status (P = 0.135). ß-Catenin is important in the pathogenesis of salivary gland PAs and ACCs. In addition, CTNNB1 exon 3 mutations do not seem to significantly influence ß-catenin cytoplasmic/membranous expression or nuclear translocation in these tumors.

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

SOX2 is a regulatory factor of embryonic stem cells that has been implicated in carcinogenesis and cancer progression. We aimed to investigate the potential role of SOX2 in the stepwise progression from pleomorphic adenoma (PA) to invasive carcinoma ex pleomorphic adenoma (CXPA), evaluating its prognostic significance as well. Thirty PAs without malignant transformation and 25 CXPAs presenting both luminal or myoepithelial differentiation (7 intracapsular and 18 extracapsular) were evaluated immunohistochemically for SOX2 expression. Of these, 24 CXPAs (96%) were positive to SOX2, being 6 intracapsular carcinomas (85.7%) and all the 18 extracapsular carcinomas (100%). Residual PA areas and PA without malignant transformation were negative. High SOX2 expression levels (> 50% of positive cells) were correlated with high histological grade (p = 0.02), brisk mitotic activity (p = 0.01), advanced pT stage (p = 0.01), tumor recurrence (p = 0.01), and development of distant metastasis (p = 0.004). Still, overall survival rates were shorter in patients with extracapsular CXPA exhibiting diffuse SOX2 expression. These results suggest that SOX2 may play an important role in carcinogenesis and progression of CXPA and is also related with prognostic indicators in CXPAs with extracapsular invasion. Although direct therapeutic intervention in SOX2 may result in unwanted complications due to its constitutive functions, strategic approach to SOX2-related pathways may provide new therapeutic opportunities for patients with invasive CXPA.