Expression of mucin (MUC) genes in mucoepidermoid carcinoma

Mucins as contrast agent targets for fluorescence-guided surgery of pancreatic cancer

Pancreatic cancer is difficult to resect due to its unique challenges, often leading to incomplete tumor resections. Fluorescence-guided surgery (FGS), also known as intraoperative molecular imaging and optical surgical navigation, is an intraoperative tool that can aid surgeons in complete tumor resection through an increased ability to detect the tumor. To target the tumor, FGS contrast agents rely on biomarkers aberrantly expressed in malignant tissue compared to normal tissue. These biomarkers allow clinicians to identify the tumor and its stage before surgical resection and provide a contrast agent target for intraoperative imaging. Mucins, a family of glycoproteins, are upregulated in malignant tissue compared to normal tissue. Therefore, these proteins may serve as biomarkers for surgical resection. Intraoperative imaging of mucin expression in pancreatic cancer can potentially increase the number of complete resections. While some mucins have been studied for FGS, the potential ability to function as a biomarker target extends to the entire mucin family. Therefore, mucins are attractive proteins to investigate more broadly as FGS biomarkers. This review summarizes the biomarker traits of mucins and their potential use in FGS for pancreatic cancer.

Prognostic impact of MUC1 and potential regulatory miR-145 and miR-21 expression in salivary mucoepidermoid carcinoma

BACKGROUND

Salivary gland mucoepidermoid carcinoma (MEC) poses a considerable risk of locoregional and distant metastasis after conventional treatments. There is an evident need for specifying prognostic biomarkers to identify patients who are in need of more intensive and prolonged follow-ups. This study aimed to assess the mucin 1 (MUC1) expression level and its potential regulatory microRNAs in salivary gland MEC and their prognostic potentials.

MATERIALS AND METHODS

The expression of MUC1 in salivary gland MEC tissues was assessed in 47 samples using immunohistochemistry. Related microRNA (miR-145 and miR-21) were evaluated using quantitative Reverse Transcription PCR. The associations between MUC1 and microRNAs expressions and clinicopathological parameters were investigated.

RESULTS

MUC1 expression levels positively correlated with histologic grade (p < 0.001), clinical stage (p = 0.04), risk of nodal metastasis (p = 0.02), as well as the likelihood of opting for radical treatment (p = 0.01). Increased expression of miR-21 (p < 0.001) and decreased expression of miR-145 (p < 0.001) were observed in MECs compared to normal salivary gland tissue. MiR-145 negatively (p = 0.01) and miR-21 positively (p = 0.01) correlated with MUC1 overexpression. Based on the univariate cox proportional hazard model, histologic grade and MUC1 expression level were significantly associated with disease-free, cancer-specific, and overall survival. However, the multivariable cox proportional hazard model indicated tumor grade as the only prognostic factor associated with disease-free survival.

CONCLUSION

Our results support the tumor suppressor role of miR-145 and the oncogenic role of miR-21 in salivary gland MEC. Also, MUC1 and miR-145 overexpression, as well as miR-21 suppression, show promising association with histologic tumor grade and clinical stage.

Expression of MUC1, MUC2 and MUC5AC in salivary gland mucoepidermoid carcinoma: A case series with diagnostic implications

Context

Mucoepidermoid Carcinoma (MEC) accounts for 10-15% of all salivary gland neoplasms and its management is related to tumour grading. The expression of mucin in the tumour cells presumably affects and predicts tumour behaviour.

Aims

To analyse the expression of MUC1 (membrane bound mucin), MUC2 and MUC5AC (secreted mucins) in mucoepidermoid carcinoma and correlate with tumour grade and patient outcome.

Settings and Design

In this retrospective correlation study the expression of MUC1, MUC2 and MUC5AC were investigated using immunohistochemistry in confirmed cases of MEC.

Methods and Material

The staining patterns of MUC1, MUC2 and MUC5AC were analysed in 10 confirmed cases from the year 2013 to 2020.

Statistical Analysis Used

SPSS 23 was used for bivariate correlations.

Results

All of the tumours expressed MUC1, showing strong membranous to focal cytoplasmic localization in all cells. The goblet cell component expressed a strong apical membranous pattern. MUC2 expression was moderate, showed cytoplasmic localisation in 40% of mucinous cells and was minimal in intermediate cells and epidermoid cells. MUC 5AC expression was strong apical membranous in goblet cells and mainly negative in intermediate cells and epidermoid cells.

Conclusions

Although MUC1 is a reliable marker for all cell types of MEC but has no significant correlation with the tumour grade. MUC 2 has not been found to be a reliable diagnostic marker and has no significant correlation with the tumour grade. MUC 5AC has been found to have a significant expression in tumours with lymphoid infiltrate. There was no statistically significant correlation of MUC expression with the site, tumour grade and patient outcome.

Expression of Mucins in Salivary Gland Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumour in both adults and children. Histological grading of MEC is subjective, but plays an important role in predicting patient prognosis. Epithelial mucin (MUC) status may aid in establishing a more accurate grade. This study aimed to investigate the expression of various mucins (MUC1, MUC2, MUC4 and MUC5AC) in MECs to determine a possible correlation with tumour grade. Fifteen cases of each tumour grade (low-, intermediate-, and high-grade) were retrieved from the pathology archives of the Department of Oral Pathology and Oral Biology at the University of Pretoria. The patients included 23 men and 22 women, and ranged from 13 to 85 years (mean 49.8 years). Sections from formalin-fixed paraffin-embedded (FFPE) tissue were used for fluorescence in situ hybridization (FISH) for MAML2 rearrangements and MUC immunohistochemical analysis. The percentage immunohistochemical expression of the neoplastic mucous cells was evaluated first, followed by the overall percentage expression of all tumour cells. The results indicated that MUC1 overexpression may be a reliable marker of high-grade MECs, whereas MUC4 overexpression may be more indicative of low-grade tumours. MUC5AC expression was considered an unreliable marker in determining grade. MUC2 was only expressed in a single case of MEC and may be considered a useful marker to exclude MEC as a diagnostic possibility. This study demonstrates that MECs show an altered MUC expression pattern that can be used for diagnostic purposes and to aid in establishing a more accurate tumour grade.

Intraductal Papilloma Arising From the Minor Salivary Glands of the Larynx: A Case Report

It is rare for intraductal papilloma, a benign papillary tumor, to occur in the salivary glands. To our knowledge, intraductal papilloma occurring in the minor salivary glands of the larynx has not been reported. In this report, we describe a case of intraductal papilloma that occurred in the minor salivary glands of the larynx. A woman in her 30s presented with hoarseness and dyspnea since a year. Fiber-optic laryngoscopy revealed a submucosal tumor involving the left aryepiglottic fold and the left false vocal fold. Computed tomography and magnetic resonance imaging revealed a 17 × 15 × 10 mm³ mass with homogenous isodensity, with regular, well-defined margins located on the left aryepiglottic fold and the left false vocal fold. Surgical resection was performed, and subsequently a diagnosis of intraductal papilloma was made by pathologic evaluation. During the follow-up period of over 3 years, the lesion has not recurred. In conclusion, intraductal papilloma of the minor salivary glands should be considered in the differential diagnosis of laryngeal submucosal tumors.

Expression of Topoisomerase II-α protein in salivary gland tumors

Salivary glands give rise to approximately 30 histological distinct tumor types, which results in a diagnostic challenge for the pathologist. The present retrospective, immunohistochemical study aimed to evaluate the expression of Topoisomerase II-α, a nuclear enzyme, as a diagnostic and prognostic marker in benign and malignant salivary gland tumors, including leomorphic adenoma, mucoepidermoid carcinoma, acinic cell carcinoma and carcinoma ex-pleomorphic adenoma. A total of 59 cases of benign and malignant salivary gland tumors were included in the present study. Representative paraffin-embedded sections were immunostained for Topoisomerase II-α (Topo II-α). The expression level was semi-quantified for each case and then correlated with the histological diagnosis using hematoxylin and eosin-stained slides, grade of tumor and total survival. Significant differences were revealed between the expression level of Topo II-α in pleomorphic adenoma and mucoepidermoid carcinoma (P<0.001), carcinoma ex-pleomorphic adenoma (P<0.001), acinic cell carcinoma (P=0.005) and a group composed of all the malignant tumors (P<0.001). Cancer-specific survival rates were insignificantly increased in tumors expressing low levels of Topo II-α (P=0.464). Thus, the present study demonstrated different expression levels of Topo II-α in benign and malignant salivary gland tumors. These differing expression levels may act as valuable biomarkers for the correct histological diagnosis. Further studies conducted on a larger scale may lead to even more conclusive results.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

Mucins are major glycoprotein components of the mucus that coats the surfaces of cells lining the respiratory, digestive, gastrointestinal and urogenital tracts. They function to protect epithelial cells from infection, dehydration and physical or chemical injury, as well as to aid the passage of materials through a tract i.e., lubrication. They are also implicated in the pathogenesis of benign and malignant diseases of secretory epithelial cells. In Human there are two types of mucins, membrane-bound and secreted that are originated from mucous producing goblet cells localized in the epithelial cell layer or in mucous producing glands and encoded by MUC gene. Mucins belong to a heterogeneous family of high molecular weight proteins composed of a long peptidic chain with a large number of tandem repeats that form the so-called mucin domain. The molecular weight is generally high, ranging between 0.2 and 10 million Dalton and all mucins contain one or more domains which are highly glycosylated. The size and number of repeats vary between mucins and the genetic polymorphism represents number of repeats (VNTR polymorphisms), which means the size of individual mucins can differ substantially between individuals which can be used as markers. In human it is only MUC1 and MUC7 that have mucin domains with less than 40% serine and threonine which in turn could reduce number of PTS domains. Mucins can be considered as powerful two-edged sword, as its normal function protects from unwanted substances and organisms at an arm's length while, malfunction of mucus may be an important factor in human diseases. In this review we have unearthed the current status of different mucin proteins in understanding its role and function in various non-communicable diseases in human with special reference to its organ specific locations. The findings described in this review may be of direct relevance to the major research area in biomedicine with reference to mucin and mucin associated diseases.

Clinicopathological and prognostic significance of MUC-2, MUC-4 and MUC-5AC expression in japanese gastric carcinomas

BACKGROUND

The mucin components of the gastric gel layer function as a protective and lubricating factor against luminal acid and proteolytic enzymes. Alteration of mucin expression in gastric preneoplastic and neoplastic lesions has suggested potential roles in neoplastic processes. This study aimed to assess the clinicopathological and prognostic significance of MUC-2, MUC-4 and MUC-5AC in Japanese gastric cancer.

METHODS

Expression of MUC-2, -4 and -5AC was evaluated on tissue microarrays of gastric carcinomas and adjacent non-cancerous mucosa specimens by immunohistochemistry and compared with clinicopathological parameters and survival time of the patients.

RESULTS

The three mucins were found to be expressed to a lesser extent in gastric carcinomas in comparison with non-cancerous mucosa (p<0.05). MUC-2 expression was negatively correlated with tumor size, depth of invasion, and TNM staging of gastric cancer (p<0.05), while that of MUC-5AC was negatively associated with the depth of invasion, venous invasion, lymph node metastasis and TNM staging (p<0.05), but positively with MUC-4 and MUC-2 expression (p<0.05). There was higher MUC-2 expression in intestinal- than diffuse-type carcinomas (p<0.05). Kaplan-Meier analysis indicated no relationship between expression of the three mucins and the cumulative survival rate of patients, even stratified according to the depth of invasion (p>0.05).

CONCLUSION

Down-regulated expression of MUC-2, -4 and -5AC may be involved in pathogenesis, invasion, metastasis or differentiation of gastric carcinoma. Their altered expression might therefore be employed as an indicator of pathobiological behavior.

The role of radiation therapy in pediatric mucoepidermoid carcinomas of the salivary glands

OBJECTIVE

To investigate the role of radiation therapy in rare salivary gland pediatric mucoepidermoid carcinoma (MEC).

STUDY DESIGN

A French multicenter retrospective study (level of evidence 4) of children/adolescents treated for MEC between 1980 and 2010 was conducted.

RESULTS

Median age of the 38 patients was 14 years. Parotid subsite, low-grade, and early primary stage tumors were encountered in 81%, 82%, and 68% of cases, respectively. All except 1 patient were treated by tumoral surgical excision, and 53% by neck dissection (80% of high grades). Postoperative radiation therapy and chemotherapy were performed in 29% and 11% of cases. With a median 62-month follow-up, overall survival and local control rates were 95% and 84%, respectively. There was 1 nodal relapse. Lower grade and early stage tumors had better survival. Postoperative radiation therapy and chemotherapy were associated with similar local rates. Patients with or without prior cancer had similar outcomes.

CONCLUSIONS

Pediatric salivary gland MEC carries a good prognosis. Low-intermediate grade, early-stage tumors should be treated with surgery alone. Neck dissection should be performed in high-grade tumors. Radiation therapy should be proposed for high grade and/or advanced primary stage MEC. For high-grade tumors without massive neck involvement, irradiation volumes may be limited to the primary area, given the risk of long-term side effects of radiation therapy in children. Pediatric MEC as second cancers retain a similar prognosis. Long-term follow-up is needed to assess late side effects and second cancers.

Mucins and toll-like receptors: kith and kin in infection and cancer

Inflammation is underlying biological phenomenon common in infection and cancer. Mucins are glycoproteins which establish a physical barrier for undesirable entry of foreign materials through epithelial surfaces. A deregulated expression and an anomalous glycosylation pattern of mucins are known in large number of cancers. TLRs are class of receptors which recognize the molecular patterns of invading pathogens and activate complex inflammatory pathways to clear them. Aberrant expression of TLRs is observed in many cancers. A highly orchestrated action of mucins and TLRs is well evolved host defence mechanism; however, a link between the two in other non-infectious conditions has received less attention. Here we present an overview as to how mucins and TLRs give protection to the host and are deregulated during carcinogenesis. Further, we propose the possible mechanisms of cross-regulation between them in pathogenesis of cancer. As both mucins and TLRs are therapeutically important class of molecules, an understanding of the underlying molecular mechanisms connecting the two will open new avenues for the therapeutic targeting of cancer.

An improved approach to diagnosing and treating conjunctival mucoepidermoid carcinoma

The current case of conjunctival mucoepidermoid carcinoma offers features that expand the biologic spectrum afforded by this tumor. More focused strategies should be developed for its earlier histopathologic diagnosis and improved management (historical recurrence rate of 85%). A 63-year-old woman with a history of rheumatoid arthritis and idiopathic sclerosing cholangitis developed scleral thinning, anterior chamber cells and flare, and uveal prolapse. Biopsies of the epibulbar lesion were initially misinterpreted as a squamous cell carcinoma but on review harbored CK7-positive cells and contained rare goblet cells brought out with Alcian blue and mucicarmine staining. Intraocular extension exhibited micro-and macrocysts with minimal goblet cells. Focal CK7 immunopositivity in any epibulbar squamous dysplasia or in invasive carcinoma should lead to suspicion of a mucoepidermoid carcinoma. Behaviorally aggressive or rapidly recurrent epithelial squamous tumors with "inflammatory" features or unusual clinical characteristics should be initially stained at multiple levels for the detection of parsimonious mucus secretion. Surgical options include wide excision and partial sclerectomy with cryotherapy for superficial invasion and/or interferon therapy. Results with radiotherapy and cryotherapy for deep scleral invasion have been unpredictable or unacceptable compared with surgery.