Mucin expression in pleomorphic adenoma of salivary gland: a potential role for MUC1 as a marker to predict recurrence

Differential Expression of Mucin in Salivary Gland Tumours

Background and Objectives: Mucin has been implicated via various mechanisms in the development and growth of tumour cells. However, mucin expression studies in salivary gland tumours are limited, especially with samples from minor salivary glands. This study aims to investigate and compare mucin expression in benign and malignant salivary gland tumours of minor and major salivary gland origins. Materials and Methods: Special stains were used to stain neutral mucin (Periodic acid Schiff), sialomucin (Alcian Blue) and sulfomucin (Aldehyde Fuschin) within tissues from six normal salivary glands and 73 salivary gland tumours including 31 pleomorphic adenomas, 27 mucoepidermoid carcinomas, and 15 adenoid cystic carcinomas. A semi-quantitative approach was used to evaluate mucin expression within ductal lumens. Sialomucin was the most expressed mucin in all salivary gland tumours, regardless of origin. Results: A significant difference was observed in the mucin expression between benign and malignant salivary gland tumours, as pleomorphic adenoma showed three times significantly higher expression of sialomucin compared to mucoepidermoid carcinoma and adenoid cystic carcinoma (p = 0.028). Pleomorphic adenomas of major glands showed 42 times significantly higher expression of sialomucin compared to those of minor glands (p = 0.000). Conclusions: Sialomucin content in pleomorphic adenomas of major glands was vastly increased compared to that in minor glands. Differential sialomucin expression in benign and malignant salivary gland tumours suggests a role in diagnosing of borderline salivary gland tumours.

Clinicopathological characteristics of pleomorphic adenoma from the labial gland: A 20-year experience with 173 cases in one single institution

OBJECTIVE

Pleomorphic adenoma (PA) of the lip is not a common phenomenon, and existing literature provides limited information on the clinicopathological features of labial PA.

STUDY DESIGN

Patients diagnosed with labial PA at our single institution over the past 20 years (2001-2020) was retrospectively screened and analyzed to investigate the epidemiologic and clinicopathological features of these tumors.

RESULTS

A total of 173 cases were screened out, and the average age was 44.3 (range 7-82) years, with a peak incidence rate during the third decade. A slight predilection for men (52%) was observed, and PA occurs more frequently in the upper lip than in the lower lip, with a ratio of 14.7:1. On clinical examination, labial PAs usually present as painless masses that develop slowly with no systemic symptoms. Histologically, labial PAs contain myoepithelial and polygonal epithelial cells in myxoid, hyaline, fibrous, chondroid, and even osseous tissues, similar to those in other sites. Specifically, 15 of 173 patients with labial PA presented with cutaneous PA.

CONCLUSION

Labial PA presents over a wide age range and dominantly occurs at the upper lip. Surgical resection is the major treatment strategy, and postoperative recurrence or malignant transformation of labial PA was extremely rare.

Recurrent pleomorphic adenoma of the parotid gland: A population-based study with emphasis on re-recurrence and malignant transformation

BACKGROUND

This study aimed to analyze the prognostic determinants for re-recurrence and malignant transformation of parotid recurrent pleomorphic adenoma (RPA).

METHODS

Between January 2011 and December 2020, all the cases of RPA of the parotid gland at our single institution were reviewed.

RESULTS

A total of 168 patients were included in this study, with a median age of 41.5 years, and 20 (11.9%) patients developed re-recurrence during follow-up. It has been evidenced that recurrence times (single or multiple) was an independent prognostic factor for recurrence-free survival (p = 0.0264). A total of 26 (15.48%) patients experienced malignant transformation of parotid RPA, and older age (>45 year old), male sex, and higher clinical tumor staging (T3-T4) were significantly associated with malignant transformation of parotid RPA.

CONCLUSIONS

Recurrence times was an independent prognostic factor for re-recurrence of parotid RPA, and older male with high T-stage may more easily develop malignant transformation.

Mammary analogue secretory carcinoma: An Indian experience of a novel entity

Aims

To explore clinical, histopathological and immunohistochemistry (IHC) features of mammary analogue secretory carcinoma (MASC) with systematic literature review.

Settings and Design

Hospital based cross-sectional study.

Subjects and Methods

The data of all cases of MASC diagnosed over a period of 1 year i.e., from July 2017 to July 2018 were retrieved. The haematoxylin and eosin (H and E) sections, and IHC sections were studied. A strict histological and recently updated criteria were applied and patients with a confirmed diagnosis of MASC were included in the study. A systematic literature review was conducted by searching the PubMed and National Centre for Biotechnology Information database.

Statistical Analysis Used

Microsoft Excel 2010.

Results

The present case series is 27th in the English literature and 1stcase series describing its histopathology in the Indian literature. The mean age of presentation is 43 years. Female preponderance was found i.e., M:F ratio of 0.5.

Conclusion

Histopathology and if necessary, followed by IHC is required for the confirmation of diagnosis of MASC. We should be aware about this recently described entity which is usually mistaken for other low grade salivary gland carcinomas like Acinic cell carcinoma (AciCC) and Mucoepidermoid carcinoma (MEC). The knowledge about its typical morphology, high degree of suspicion and IHC confirmation with both S-100 and Mammaglobin help in precise diagnosis.

MUC4 is a valuable marker for distinguishing secretory carcinoma of the salivary glands from its mimics

AIMS

Secretory carcinoma (SC) (synonym: mammary analogue secretory carcinoma) is a low-grade salivary gland tumour that occurs in both major and minor salivary glands. SC is known for its wide morphological, architectural and immunohistochemical spectrum, which overlaps with those of several salivary gland neoplasms, including acinic cell carcinoma (AciCC) and intercalated duct-type intraductal carcinoma (IDC) in major salivary glands, and polymorphous adenocarcinoma (PAC) in minor salivary glands. These tumours share with SC some morphological features and SOX10 immunoreactivity; also, with the exception of AciCC, they all coexpress S100 and mammaglobin.

METHODS AND RESULTS

We compared MUC4 and mammaglobin expression in 125 salivary gland carcinomas (54 genetically confirmed SCs, 20 AciCCs, 21 PACs, and 30 IDCs) to evaluate the potential of these two markers to differentiate these entities. Moderate to strong diffuse MUC4 positivity was detected in 49 SCs (90.7%), as compared with none of the IDCs and PACs. In contrast, mammaglobin was frequently expressed in SCs (30 of 36 cases; 83.3%), IDCs (24/28; 85.7%), and PACs (7/19; 36.8%). Two of three high-grade SCs lost MUC4 expression in the high-grade tumour component. No significant correlation was found between MUC4 expression and the fusion variant in SC (ETV6-NTRK versus non-ETV6-NTRK).

CONCLUSION

The results of our study identify MUC4 as a sensitive (90.7%) and specific (100%) marker for SC, with high positive (100%) and negative (93.4%) predictive values. Thus, MUC4 may be used as a surrogate for SC in limited biopsy material and in cases with equivocal morphology.

Molecular cytogenetic pilot study on pleomorphic adenomas of salivary glands

Pleomorphic adenomas (PAs) of salivary glands are the most frequent entity of solid parotid tumors. Nonetheless, their genetics is not yet well understood. Thus, the current study characterized 14 PAs using a unique combination of cytogenetic, molecular cytogenetic and/or molecular karyotyping based approaches. The current study applied G-banding based on trypsin treatment and Giemsa-staining in peripheral blood and tumor tissue. Additionally, fluorescence in situ hybridization was performed using whole chromosome painting or centromeric probes. Array-based comparative genomic hybridization was also conducted. In 5 of 14 cases, chromosomal and/or submicroscopic alterations were characterized. Balanced and unbalanced translocations, loss or gain of whole chromosomes and submicroscopic copy number alterations were detected. Furthermore, the first case of a so-called ‘jumping translocation’ in a PA was reported. The genes twist-related protein 1 and distal-less homeobox 5 were also involved in copy number variations in two PAs. In conclusion, approaches utilized in the current study are highly suited to characterize the genetic constitution of PAs.

Pleomorphic Adenoma in the Lower Lip: A Case Report and a Review

Pleomorphic adenoma constitutes 50% of salivary gland tumors affecting mostly the parotid gland extraorally, and the palate intraorally. While the upper lip is a common site, it is unusual to encounter this tumor in the lower lip. A 26-year-old man complained of a persistent lump affecting the lower lip. The lesion was excised and was shown on histopathological examination to be a pleomorphic adenoma with squamous metaplasia. At the 18-month review appointment, there was complete healing and no recurrence. Pleomorphic adenoma in the lower lip should be considered among the differential diagnosis of lower labial swellings, especially in young patients. There needs to be reconsideration of the epidemiological and histological characteristics.

Estrogen Receptor, Progesterone Receptor, and HER-2 Expression in Recurrent Pleomorphic Adenoma

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm and, although mostly benign, recurrences, being called recurrent pleomorphic adenoma (RPA) and malignant transformation to carcinoma ex pleomorphic adenoma (CXPA), do occur. Recently, attention has been focused on molecular targeted cancer therapy in various tumors, including salivary gland tumors. The aim of this study was to investigate the role of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) in PA, RPA, and CXPA. In total, 20 cases of PA, 18 of RPA, and 7 cases of CXPA were immunohistochemically studied for ER, PR, and HER-2. For evaluation of ER and PR, only nuclear expression and greater than 10% positive cells were regarded as cutoff criteria. HER-2 was evaluated semiquantitatively and graded from 0 to 3+. HER-2 amplification was assessed by chromogenic in situ hybridization (CISH). Tumors were negative for ER, PR, and HER-2 in all cases of PA and RPA. A case of CXPA showed moderate and complete membranous staining, and 6 cases were negative. HER-2 amplification was not observed in any case. In conclusion, the lack of ER, PR, and HER-2 expression in PA, RPA, and CXPA suggests that these proteins are not involved in progression, recurrence, or malignant transformation of PA.

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.

Mammary analogue secretory carcinoma of salivary glands: diagnostic pitfall with distinct immunohistochemical profile and molecular features

Mammary analogue secretory carcinoma (MASC) is a newly defined entity among salivary gland malignancies which has just been established in the 4^th edition of the WHO classification of head and neck tumors. MASC (synonym: secretory carcinoma) are characterized by a specific rearangement of the ETV6 gene locus. Here, we present a series of 3 MASC cases including clinical data with follow-up for up to 26 months. All tumours immunhistochemically displayed strong positivity for cytokeratin 7, and mammaglobin, focal positivity for S100, cytokeratin 5/6 and muc-4. In contrast, immunhistochemical stainings against cytokeratin 14, hormon receptors, Her2/neu, androgen receptor and prostate-specific antigen were consistently negative. FISH analysis showed translocation of the ETV6 gene locus in the majority of tumour cell nuclei. During clinical follow-up, no local relapse or metastasis was detected. As these carcinomas are clinically and radiologically indistinguishable from other salivary gland tumours and as therapeutic approaches and prognosis might differ, we need to be able to diagnose MASC correctly.

Why Do Parotid Pleomorphic Adenomas Recur? A Systematic Review of Pathological and Surgical Variables

Background

The recurrence of pleomorphic adenoma (PA) has been extensively debated, mostly in relation to the extent of parotidectomy.

Methods

A systematic review was undertaken to clarify the surgical and pathological variables related to PA recurrence. Inclusion criteria were as follows: English literature, and prospective or retrospective studies. Exclusion criteria were as follows: single case reports, reviews, and lack of PA recurrence data.

Results

Pathology-related variables associated with recurrence include the histological subtype, the thickness and incompleteness of the tumor capsule, pseudopodia, and satellite nodules. Surgery-related variables associated with recurrence are the presence of intact margins and tumor puncture or spillage. Other factors are the size of the tumor and the age of patient. Myxoid subtypes of PA tend to have incomplete and thinner capsules and to recur more frequently. Surgical variables related to recurrence include positive margins and tumor spillage.

Conclusion

Myxoid and/or large PA, especially in young patients, should be approached more cautiously to avoid recurrences.

Pleomorphic Adenoma of Cheek Masquerading as Fibrolipoma - Case Report with Review

Salivary gland tumours are rare, comprising 3% of head and neck tumours, of which Pleomorphic Adenoma (PA) constitutes 70-80%. It accounts for 53-74% of parotid tumours, 44-68% submandibular gland tumours and 38-43% of minor salivary gland tumours. It usually presents as painless, firm, slow growing mobile mass. Various diagnostic modalities for early detection of the tumour include FNAC, Ultrasonography, CT and MRI. The choice of treatment of pleomorphic adenoma of the minor salivary glands depends on the aggressiveness of the tumour, the extension of the mass, and its relation with the vital structures. Here, we report a rare case of pleomorphic adenoma of minor salivary glands of cheek in a 40-year-old male patient with emphasis on various diagnostic modalities.

MUC-1 expression in pleomorphic adenomas using two human milk fat globule protein membrane antibodies (HMFG-1 and HMFG-2)

Pleomorphic adenoma (PA) is the most common salivary gland tumor and its microscopic features and histogenesis are a matter of debate. Human milk fat globule protein membrane (HMFG) monoclonal antibodies (MoAbs) comprise a set of antibodies against the mucin 1 (MUC-1) protein detected in several salivary gland tumors.

Epithelial and stromal patterns of pleomorphic adenoma of minor salivary glands: A histopathological and histochemical study

Background:

Pleomorphic adenoma (PA) accounts for 45–74% of all the salivary gland neoplasms, of which 40–70% are present in minor salivary glands. Studies have depicted variations in histological typing and classification of these tumors. Its pleomorphism is attributed to the cytological differentiations of the epithelial components and the diverse stromal components. Biochemical investigations of saliva have revealed “mucins” to be its main component. Mucins reflect in their composition, the functional state of the mucosa, both in health and disease. Many reviews on histochemical classification and identification have been put forward to explain the intricacies of mucins; however, no attempts have been made to classify salivary gland tumors based on their mucin profiles and assess its prognostic significance. Thus, this study was executed to analyze the clinical, histopathological and histochemical behavior of PA of minor salivary glands and decipher a correlation.

Materials and Methods:

Twenty-six diagnosed cases of PA of minor salivary glands and five controls of normal minor salivary glands of the hard palate were included in the study. Blocks were retrieved, sectioned and stained with hematoxylin and eosin (H and E) stain as well as combined Alcian blue (AB)-periodic acid-Schiff (PAS) stains.

Results:

The stained slides revealed an array of epithelial and stromal patterns and varying heterogeneity of mucin expression of normal and neoplastic minor salivary glands.

Conclusion:

The study elucidated the role of mucins in tumorigenesis and its prognostic implications.

Etiology and management of recurrent parotid pleomorphic adenoma

The objective of this review study was to encompass the relevant literature and current best practice options for this challenging, sometimes incurable problem. The source of the data was Ovid MEDLINE from 1946 to 2014. Review methods consisted of articles with clinical correlates. The most important cause of recurrence is enucleation with rupture and incomplete tumor excision at operation. Incomplete pseudocapsule, extracapsular extension, pseudopods of pleomorphic adenoma tissue, and satellite pleomorphic beyond the pseudocapsule are also likely linked to recurrent pleomorphic adenoma. Most recurrent pleomorphic adenoma are multinodular. Magnetic resonance imaging is the imaging study of choice for recurrent pleomorphic adenoma. Nerve integrity monitoring may reduce morbidity for recurrent pleomorphic adenoma. Treatment of recurrent pleomorphic adenoma must be individualized. Total parotidectomy, given the multicentricity of recurrent pleomorphic adenoma, is appropriate in many patients, but may be inadequate to control recurrent pleomorphic. There is accumulating evidence from retrospective series that postoperative radiation therapy results in significantly better local control.

Human prominin-1 (CD133) is detected in both neoplastic and non-neoplastic salivary gland diseases and released into saliva in a ubiquitinated form

Prominin-1 (CD133) is physiologically expressed at the apical membranes of secretory (serous and mucous) and duct cells of major salivary glands. We investigated its expression in various human salivary gland lesions using two distinct anti-prominin-1 monoclonal antibodies (80B258 and AC133) applied on paraffin-embedded sections and characterized its occurrence in saliva. The 80B258 epitope was extensively expressed in adenoid cystic carcinoma, in lesser extent in acinic cell carcinoma and pleomorphic adenoma, and rarely in mucoepidermoid carcinoma. The 80B258 immunoreactivity was predominately detected at the apical membrane of tumor cells showing acinar or intercalated duct cell differentiation, which lined duct- or cyst-like structures, and in luminal secretions. It was observed on the whole cell membrane in non-luminal structures present in the vicinity of thin-walled blood vessels and hemorrhagic areas in adenoid cystic carcinoma. Of note, AC133 labeled only a subset of 80B258–positive structures. In peritumoral salivary gland tissues as well as in obstructive sialadenitis, an up-regulation of prominin-1 (both 80B258 and AC133 immunoreactivities) was observed in intercalated duct cells. In most tissues, prominin-1 was partially co-expressed with two cancer markers: carcinoembryonic antigen (CEA) and mucin-1 (MUC1). Differential centrifugation of saliva followed by immunoblotting indicated that all three markers were released in association with small membrane vesicles. Immuno-isolated prominin-1–positive vesicles contained CEA and MUC1, but also exosome-related proteins CD63, flotillin-1, flotillin-2 and the adaptor protein syntenin-1. The latter protein was shown to interact with prominin-1 as demonstrated by its co-immunoisolation. A fraction of saliva-associated prominin-1 appeared to be ubiquitinated. Collectively, our findings bring new insights into the biochemistry and trafficking of prominin-1 as well as its immunohistochemical profile in certain types of salivary gland tumors and inflammatory diseases.

Pleomorphic adenoma of oral minor salivary glands: An investigation of its neoplastic potential based on apoptosis, mucosecretory activity and cellular proliferation

OBJECTIVE

The aim of this study was to investigate the neoplastic potential of the PA of minor oral salivary glands measured by apoptosis (Bcl-2, Bax and p53), mucosecretory activity (MUC1), and cellular proliferation (Ki-67).

DESIGN

Thirty-one cases of PA of the oral cavity and four controls (C) taken from normal oral minor salivary glands were analyzed using the immunohistochemistry technique. The proteins were detected utilizing a semi-quantitative method (scores) as follows: (-) negative ≤5%, (+) low 6-25%, (++) moderate 26-50% and (+++) high >50% of positive tumour cells. The apoptotic indices were evaluated by the ratio Bcl-2/Bax. Non-parametric comparison and correlation tests were used for analysis.

RESULTS

The data showed high staining of anti-apoptotic protein Bcl-2 in both groups (PA=57.9%; C=67.7%) and a significantly lower expression of pro-apoptotic protein Bax (PA=22.7%; C=97.7%) and MUC1 (PA=14%; C=82.3%) in PA than in C (p<0.001). On the other hand, a similar expression of Ki-67 and p53 proteins (≤5%) was seen in both PA and C. In PA, only 2/31 cases showed the ratio Bcl-2/Bax<1.There was no difference in cellular expression with regard to clinical variables or clinical outcome (p>0.05).

CONCLUSION

The neoplastic potential of PA could be associated with an imbalance in apoptotic processes and a lower index of cellular proliferation. Mucosecretory activity does not play a significant role in primary PA.

Pleomorphic adenoma of the nasal septum

INTRODUCTION

Pleomorphic adenoma is the most common benign tumour of the salivary glands. The major salivary glands are most commonly involved, or more rarely accessory salivary glands, especially the oral cavity. Other locations, such as the nasal cavity, paranasal sinuses or upper aerodigestive tract, are exceptional.

CASE REPORT

A 26-year-old female presented with right-sided nasal obstruction. Radiology found a lesion involving the anterior third of the nasal septum. The patient underwent complete surgical resection of the tumour via an endonasal approach. Histological examination found a mixed cellular component (epithelial and myoepithelial) and mesenchymatous tissue with chondromyxoid stroma, enabling diagnosis of a typical pleomorphic adenoma.

DISCUSSION/CONCLUSION

Pleomorphic adenoma is exceptional in the nasal cavity, with only a few cases reported in the literature. Although benign, the risk of local recurrence, malignant transformation and metastasis requires close long-term follow-up.

Massive transcranial parotid pleomorphic adenoma: recurrence after 30 years

Pleomorphic adenoma, also known as benign mixed tumor, is the most common tumor affecting the parotid gland and can reach massive size; however, intracranial invasion is rare. Recurrence of pleomorphic adenoma after excision is a well-known phenomenon and can present decades after resection of the primary tumor. Here we present the case of a 53-year-old man who presented to our clinic with ear fullness, otalgia, and hearing loss 30 years after undergoing total parotidectomy and external beam radiotherapy for pleomorphic adenoma. Magnetic resonance imaging revealed a massive transcranial tumor invading the mastoid cavity, the dura of the posterior fossa, the fallopian and semicircular canals, the jugular foramen, the lateral infratemporal fossa skull base, the sigmoid and transverse sinuses, and the superior parapharyngeal region. Gross examination and histopathological studies confirmed that the mass was a recurrent pleomorphic adenoma. Here we discuss the features of recurrent pleomorphic adenoma and review the current literature.

MUC4: a novel prognostic factor of oral squamous cell carcinoma

MUC4 mucin is now known to be expressed in various normal and cancer tissues. We have previously reported that MUC4 expression is a novel prognostic factor in several malignant tumors; however, it has not been investigated in oral squamous cell carcinoma (OSCC). The aim of our study is to evaluate the prognostic significance of MUC4 expression in OSCC. We examined the expression profile of MUC4 in OSCC tissues from 150 patients using immunohistochemistry. Its prognostic significance in OSCC was statistically analyzed. MUC4 was expressed in 61 of the 150 patients with OSCC. MUC4 expression was significantly correlated with higher T classification (p = 0.0004), positive nodal metastasis (p = 0.049), advanced tumor stage (p = 0.002), diffuse invasion of cancer cells (p = 0.004) and patient's death (p = 0.004) in OSCC. Multivariate analysis showed that MUC4 expression (p = 0.011), tumor location (p = 0.032) and diffuse invasion (p = 0.009) were statistically significant risk factors. Backward stepwise multivariate analysis demonstrated MUC4 expression (p = 0.0015) and diffuse invasion (p = 0.018) to be statistically significant independent risk factors of poor survival in OSCC. The disease-free and overall survival of patients with MUC4 expression was significantly worse than those without MUC4 expression (p < 0.0001 and p = 0.0001). In addition, the MUC4 expression was a significant risk factor for local recurrence and subsequent nodal metastasis in OSCC (p = 0.017 and p = 0.0001). We first report MUC4 overexpression is an independent factor for poor prognosis of patients with OSCC; therefore, patients with OSCC showing positive MUC4 expression should be followed up carefully.

Recent advances in mucin immunohistochemistry in salivary gland tumors and head and neck squamous cell carcinoma

This review focuses on the immunohistochemical expression of members of the MUC-type mucin family in salivary gland tumors and head and neck squamous cell carcinomas (HNSCC). Information is available on changes in the expression levels and distribution profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6 and MUC7 in tumors of the salivary glands; and of MUC1, MUC2 and MUC4 in HNSCC. In salivary gland tumors the expression patterns of MUC2, MUC3, MUC5AC and MUC6 appear to be very closely correlated with the histopathological tumor type indicating their potential use to improve diagnostic accuracy in salivary gland neoplasia. Some MUC-type mucins have emerged as valuable prognostic indicators in pleomorphic adenoma, mucoepidermoid carcinoma and HNSCC. Nine antibodies directed against different MUC1 antigens have thus far been examined in HNSCC of which monoclonal antibodies DF3, HMFG-1 and Ma695 have shown significant correlations with disease outcome. The importance of taking the specific anti-MUC antibody into consideration when comparing the results of different studies on MUC expression in salivary gland tumors and HNSCC is also highlighted in this review.

Development of human minor salivary glands: expression of mucins according to stage of morphogenesis

The formation of salivary glands entails the proliferation of epithelial cells from the stomatodeum into the underlying ectomesenchyme, culminating in a complex network of ducts and acinar bulbs. The extent to which mucins regulate this process is unknown, but they appear to mediate luminal space formation and maturation. Our aim was to examine mucin expression patterns during the morphogenesis of human salivary glands. Mucin expression - MUC1, 2, 3, 4, 5AC, 5B, 6, and 16 - was analyzed in specimens of developing human salivary glands, obtained from fetuses at 4-24 weeks' gestation, and fully developed salivary glands by immunohistochemistry. Expression patterns were analyzed qualitatively according to the development stage of the salivary glands. Mucins 1, 3, 4, 5B, and 16 were expressed during salivary gland development - being stronger in all ductal segments by the final phases of branching morphogenesis and in mature glands. Acinar cells were negative for most mucins, including MUC1 in mature salivary glands. Mucins 2, 5AC, and 6 were not expressed. Mucins MUC1, 3, 4, 5B, and 16 are expressed in developing human salivary glands and in mature glands, suggesting important roles in the maturation and maintenance of the ductal network.

Increased mucin 1 expression in recurrence and malignant transformation of salivary gland pleomorphic adenoma

AIMS

Pleomorphic adenoma (PA) is the most common salivary gland tumour with a tendency to recur (RPA) and a risk of malignant transformation. Mucin 1 (MUC-1) plays a role in the progression of many tumours and may be a marker to predict RPA. The aim of this study was to evaluate MUC-1 expression in different phases of the adenoma to carcinoma sequence.

METHODS AND RESULTS

Twenty-one cases of PA, 18 cases of RPA, three cases of RPA with focal transformation (TRPA) and 11 cases of carcinoma ex-pleomorphic adenoma (CXPA) were analysed immunohistochemically for MUC1 expression using an antibody to MUC1/DF3. MUC1 reactivity in RPA was stronger than that observed in PA and, in all the different carcinoma groups, MUC-1 expression was significantly higher in carcinoma than in RPA and PA.

CONCLUSION

This study has confirmed that MUC-1 is related to the recurrence of PA and that this molecule is associated with malignant transformation of PA with carcinoma cells overexpressing MUC-1.

Study of histopathological, morphological and immunohistochemical features of recurrent pleomorphic adenoma: an attempt to predict recurrence of pleomorphic adenoma

BACKGROUND

Recurrent pleomorphic adenoma (RPA) is an uncommon and challenging disease. The aim of this study was to review the clinical information obtained by examining RPA patients, to determine its histomorphological features and to verify the expression of the Mcm-2 markers of cell proliferation and the expression of p-53 in pleomorphic adenoma (PA), RPA, and RPA with malignant transformation (TRPA).

METHODS

A total of 10 cases of PA and 29 cases of RPA were examined in detail for the presence of nodules and their histomorphological features. Cell proliferation and expression of p-53 were detected by the immunohistochemical technique using the antibodies against Mcm-2 and p-53.

RESULTS

Histopathologically, RPA is very similar to PA; the only difference found was that all the cases of RPA were multinodular. When comparing primary and recurrent tumor, no significant difference was found in terms of cell proliferation and the expression of p-53; however, in the RPA with areas of malignant transformation there was an increased expression of these proteins.

CONCLUSION

This study showed that recurrences were multinodular, with nodules varying in numbers and sizes. No significant difference in histological features was found between RPA and PA. Moreover, the immunohistochemical study showed a low expression of p-53 and Mcm-2 in PA and RPA and an increased expression of these proteins in the RPA with areas of malignant transformation.

MUC1 and the simple mucin-type antigens: Tn and Sialyl-Tn are differently expressed in salivary gland acini and ducts from the submandibular gland, the vestibular folds, and the soft palate

OBJECTIVE AND DESIGN

Autopsies of the submandibular gland, the vestibular folds and the soft palate from 65-87 old humans were examined to record the immunohistochemical expression of MUC1 and the simple mucin-type antigens Tn and Sialyl-Tn.

RESULTS

(1) The serous acini in the submucosal glands from the larynx and the soft palate expressed MUC1-associated glycans that were not detectable in the serous acini from the submandibular gland. (2) Virtually all the submucosal acini at oral site of the soft palate are mucous, and in contrast to mucous acini in the vestibular folds and submandibular gland, the palatinal acini in the submucosa underneath the oral mucosa showed a well-defined cytoplasmic reaction with anti-MUC1 antibodies as wells as with anti-Tn. (3) Both the mucous acini and the ducts at the oral site of the soft palate showed reaction for Sialyl-Tn while in the vestibular folds and in the submandibular gland expression for this carbohydrate was observed only in the acini. (4) The staining obtained after incubation with the Tn antibodies showed no cross localization with the staining obtained after incubation with an anti-A blood group antibody. (5) All the autopsies showed reaction in the glands after incubation with the MUC1 antibodies while some autopsies reacted with the anti-Tn antibodies and/or with the anti-Sialyl-Tn antibodies and others did not.

CONCLUSION

The mucin expression in the acini and ducts from the upper human aerodigestive tract strongly depended on the location of the glandular tissue.

Angiogenic and lymphangiogenic microvessel density in recurrent pleomorphic adenoma

BACKGROUND

Recurrent pleomorphic adenoma (RPA) is an uncommon and challenging disease. The aim of this study was to determine if there is a difference between RPA and the pleomorphic adenoma (PA) without recurrence related to tumor blood and lymphatic vascularization. Moreover, we compared the microvessel density (MVD) between cell-rich areas (predominance of epithelial cells) and cell-poor areas (predominance of myxoid and chondroid areas) of the stroma of PA and RPA. In addition, immunohistochemical staining for the Ki-67 antigen was conducted simultaneously to evaluate cell proliferation in PA and RPA.

METHODS

A total of 19 cases of PA and 24 cases of RPA, blood, and lymphatic vessels were analyzed by immunohistochemical technique using the antibodies CD34, CD105, D2-40, and Ki-67.

RESULTS

Comparing no recurrent with recurrent tumor, no significant difference was found in terms of lymphatic vessel density, MVD, and proliferation index. When MVD and proliferation index were compared with different areas in cellular composition (cell-rich and cell-poor areas), there was a significant difference in PA, as well as in RPA.

CONCLUSION

This study shows that although RPA presents more aggressive clinical behavior than PA, there is no difference between tumor blood and lymphatic vascularization, suggesting that there is no correlation between vascularity and risk of recurrence. Furthermore, vascularized stroma in PA, as well as RPA, depends on the proportion of the cellular composition.

Recurrence of pleomorphic adenoma of the parotid gland--predictive value of cadherin-11 and fascin

The predictive value of cadherin-11, tenascin, fascin, and mucin-1 as markers for the likelihood of recurrence in pleomorphic adenoma of the parotid gland was examined. In this retrospective study we analysed 20 tumours from16 patients by immunohistochemistry. Staining intensities were measured using a semiquantitative scoring approach; localisation (tumour centre vs border) as well as clinical data were analysed and correlated with follow-up. Cadherin-11 was increased in recurrent tumours. However, no changes of fascin, tenascin or mucin-1 were observed. Cadherin-11 and fascin were increased in primary tumours of patients with later recurrence, with fascin upregulation restricted to the tumour border. In conclusion, cadherin-11 and fascin should be further analysed for their value as markers for later recurrence in pleomorphic adenoma. Our observations might reflect dysregulation of cellular pathways contributing to cellular dissemination, which might potentially result in later recurrence.

Precursor lesions of pancreatic cancer

This review article describes morphological aspects, gene abnormalities, and mucin expression profiles in precursor lesions such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN) of the pancreas, as well as their relation to pancreatic ductal adenocarcinoma (PDAC). The gene abnormalities in precursors of PDAC are summarized as follows: (1) KRAS mutation and p16/CDKN2A inactivation are early events whose frequencies increase with the dysplasia grade in both PanIN and IPMN; (2) TP53 mutation and SMAD4/DPC4 inactivation are late events observed in PanIN3 or carcinomatous change of IPMN in both PanIN and IPMN, although the frequency of the TP53 mutation is lower in IPMN than in PDAC; and (3) also in MCN, KRAS mutation is an early event whose frequency increases with the dysplasia grade, whereas TP53 mutation and SMAD4/DPC4 inactivation are evident only in the carcinoma. The mucin expression profiles in precursors of PDAC are summarized as follows: (1) MUC1 expression increases with the PanIN grade, and is high in PDAC; (2) the expression pattern of MUC2 differs markedly between the major subtypes of IPMN with different malignancy potentials (i.e., IPMN-intestinal type with MUC2+ expression and IPMN-gastric type with MUC2- expression); (3) MUC2 is not expressed in any grade of PanINs, which is useful for differentiating PanIN from intestinal-type IPMN; (4) de novo expression of MUC4, which appears to increase with the dysplasia grade; and (5) high de novo expression of MUC5AC in all grades of PanINs, all types of IPMN, MCN, and PDAC.

MUC-1 mucin in normal human salivary glands detected by HMFG-1 and HMFG-2 monoclonal antibodies

The aim of this study was to determine the immunoexpression of normal salivary gland cells using two human milk fat globule membrane protein antibodies (HMFG-1 and HMFG-2). Paraffin-embedded, 5 microm-thick slides from parotid and submandibular gland tissues were cut and immunostained with monoclonal antibodies HMFG-1 and HMFG-2 against MUC1 protein. HMFG antigens were found in secretory epithelial cells and ductal cells lining the striated and intercalated ducts in the intraductal secretion material, and sometimes in the myoepithelial cells. Our results suggest that HMFG-1 and HMFG-2 proteins may play a role in normal salivary gland function, mainly in the manufacturing and secretion of saliva.

Management and prognostic factors of recurrent pleomorphic adenoma of the parotid gland: personal experience and review of the literature

The aim of this study was to investigate the management and prognostic determinants of recurrent pleomorphic adenoma (RPA). A retrospective analysis was performed to examine the clinical features, the prevalence of surgical complications, and new recurrences of RPA. Tumor recurrence rate was estimated by the Kaplan–Meier method, and the prognostic value of some of the variables was tested by univariate analysis using the log rank test. The study focused on 33 patients, 18 female (54.5%) and 15 male (45.5%), aged 12–71 years (median 41). A total or extended total parotidectomy was performed in 16 cases (48.5%), a superficial parotidectomy in 10 cases (30.3%), and a local excision in 7 cases (21.2%). In ten patients (30.3%), a branch or the trunk of the facial nerve was deliberately sacrificed. Major complications included one unexpected definitive paralysis of the marginal mandibular branch of the facial nerve and 14 cases of Frey syndrome. Follow-up varied from 2 to 25 years (median 10.5 years), and there were 11 new recurrences (33.3%) within a period varying from 1 to 16 years (median 6 years). The estimated tumor recurrence rates were 14.1 ± 6.6% at 5 years, 31.4 ± 9.4% at 10 years, 43.0 ± 10.8% at 15 years, and 57.2 ± 14.8% at 20 years. Presence of a multinodular lesion and the type of intervention performed were significantly associated with a higher probability of recurrence. RPAs are prone to new recurrences, especially when multinodular and treated with a local excision. Surgical treatment should include facial nerve resection in selected cases. Follow-up for the patient’s lifetime is warranted.

[MUC1 (EMA): A key molecule of carcinogenesis?]

MUC1 is a large trans-membrane highly glycosylated mucin which is expressed at the apical pole of normal cells in glandular epithelia. MUC1 is implicated in many physiological mechanisms such as adhesion, development and differentiation. Also, MUC1 is frequently deregulated and over-expressed with a membrane circumferential and/or cytoplasmic expression. The intracellular tail of MUC1 is phosphorylated and can interact with many signalling proteins and transcriptional factors. Indeed, MUC1 can interact with B-catenin competitively for E-cadherin, thus destabilizing intercellular junctions and favouring metastatic dissemination. In carcinomas, the overexpression and membrane delocalization of MUC1 is associated with a worse prognosis and a shorter survival in breast, colon, kidney, prostate or gastro-intestinal cancers. MUC1 appears to be a novel therapeutic target for immunotherapy or anti-tumour vaccines.

A mucoadhesive in situ gel delivery system for paclitaxel

MUC1 gene encodes a transmembrane mucin glycoprotein that is overexpressed in human breast cancer and colon cancer. The objective of this study was to develop an in situ gel delivery system containing paclitaxel (PTX) and mucoadhesives for sustained and targeted delivery of anticancer drugs. The delivery system consisted of chitosan and glyceryl monooleate (GMO) in 0.33M citric acid containing PTX. The in vitro release of PTX from the gel was performed in presence and absence of Tween 80 at drug loads of 0.18%, 0.30%, and 0.54% (wt/wt), in Sorensen's phosphate buffer (pH 7.4) at 37 degrees C. Different mucin-producing cell lines (Calu-3>Caco-2) were selected for PTX transport studies. Transport of PTX from solution and gel delivery system was performed in side by side diffusion chambers from apical to basal (A-B) and basal to apical (B-A) directions. In vitro release studies revealed that within 4 hours, only 7.61% +/- 0.19%, 12.0% +/- 0.98%, 31.7% +/- 0.40% of PTX were released from 0.18%, 0.30%, and 0.54% drug-loaded gel formulation, respectively, in absence of Tween 80. However, in presence of surfactant (0.05% wt/vol) in the dissolution medium, percentages of PTX released were 28.1% +/- 4.35%, 44.2% +/- 6.35%, and 97.1% +/- 1.22%, respectively. Paclitaxel has shown a polarized transport in all the cell monolayers with B-A transport 2 to 4 times higher than in the A-B direction. The highest mucin-producing cell line (Calu-3) has shown the lowest percentage of PTX transport from gels as compared with Caco-2 cells. Transport of PTX from mucoadhesive gels was shown to be influenced by the mucin-producing capability of cell.

Vascular endothelial growth factor in salivary pleomorphic adenomas: one of the reasons for their poorly vascularized stroma

To better understand the poorly vascularized background of the stroma of pleomorphic adenomas, we attempted to determine the expression of molecules related to blood vessels and hypoxic conditions in pleomorphic adenoma. Surgical specimens and tumor cells in primary culture of salivary pleomorphic adenomas were used for immunohistochemistry for CD31, vascular endothelial growth factor (VEGF) and its receptors Flk-1 and Flt-1, as well as for hypoxia markers, such as hypoxia-inducible factor-1alpha (HIF-1alpha) and lactate dehydrogenase-1 (LDH). At the same time, alternative splicing modes of the VEGF gene and expression levels of the HIF-1alpha gene were analyzed in surgical specimens by means of reverse-transcription polymerase chain reaction (RT-PCR) and direct sequencing of the PCR products. In addition to co-immunolocalization with CD31+ vascular endothelial cells, VEGF and its receptors were demonstrated in normal duct epithelial and myoepithelial cells as well as in tumor cells in ductal structures and in myxochondroid stromata. Immunolocalizations for HIF-1alpha and LDH were confirmed in the VEGF-positive area. Immunofluorescence signals for VEGF and others were confirmed in pleomorphic adenoma cells in culture. RT-PCR results showed that there were at least four splicing modes of the VEGF gene, among which VEGF(121) was most enhanced, and higher HIF-1alpha levels in pleomorphic adenomas. The results suggest that pleomorphic adenoma cells produce VEGF in several functional forms for their own proliferation or differentiation, and that the VEGF expression is controlled by hypoxic circumstances of poorly vascularized pleomorphic adenomas.