MUC4 and ERBB2 expression in major and minor salivary gland mucoepidermoid carcinoma

Systemic therapies for salivary gland carcinoma (excluding adenoid cystic carcinoma): REFCOR recommendations by the formal consensus method

OBJECTIVE

To determine the therapeutic indications for systemic medical treatment in the management of salivary gland carcinoma (excluding adenoid cystic carcinoma) according to the clinical situation.

MATERIALS AND METHODS

The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group who drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group, according to the formal consensus method.

RESULTS

Salivary gland carcinoma is rare and there is currently insufficient evidence to indicate chemotherapy at the localized stage. At the metastatic stage, initial management can be based on a phase of monitoring for indolent disease. Some histological subtypes (salivary duct carcinoma and adenocarcinoma) are more aggressive and require systemic treatment from the outset. To guide systemic treatment, it is recommended to perform immunohistochemistry and molecular biology analyses (overexpression of HER2 and androgen receptors, NTRK fusion, next-generation sequencing).

CONCLUSION

Salivary gland carcinoma is a rare tumor for which there are currently few effective medical treatments. It is therefore recommended to include patients in clinical trials.

Genomics and tumor microenvironment of breast mucoepidermoid carcinoma based on whole-exome and RNA sequencing

Mammary mucoepidermoid carcinoma (MEC) is a rare entity. The molecular characteristics of breast MEC have not been fully investigated due to its rarity. We performed a retrospective study among 1000 patients with breast carcinomas and identified four cases of breast MEC. Clinical and demographic data were collected. Immunohistochemistry panels which were used to diagnose salivary gland MEC and breast carcinomas were also performed. MAML2 rearrangements were detected by FISH and fusion partners were identified by RNA sequencing. Whole-exome sequencing (WES) was used to reveal the genomes of these four breast MEC. Then, the biological functions and features of breast MEC were further compared with those of invasive breast carcinomas and salivary gland MEC.According to Ellis and Auclair's methods, these four breast MEC could be classified as low-grade breast MEC. All the patients were alive, and disease-free survival (PFS) ranged from 20 months to 67 months. Among these four breast MEC, two cases were triple-negative, and the other two cases were found to be ER positive, with one also showing HER2 equivocal by immunohistochemical staining, but no amplification in FISH. FISH analysis confirmed the presence of the MAML2 translocation in three of four tumors, and CRTC1-MAML2 fusion was confirmed in two of them by RNA-sequencing. The average coverage size of WES for the tumor mutation burden estimation was 32 Mb. MUC4, RP1L1 and QRICH2 mutations were identified in at least three tumors, and these mutation also existed in breast invasive carcinoma databases (TCGA, Cell 2015; TCGA, Nature 2012). The results showed that there were many genes in breast MEC overlapping with the breast invasive carcinoma databases mentioned above, range from 5 to 63 genes (median:21 genes). Next, we assessed immune cell infiltration levels in these tumors. In all these tumors, M2 macrophages and plasma cell were in the high infiltration group. Our breast MEC showed different results from the salivary gland MEC, whose plasma cells were in the low infiltration group. Overall, we first analyzed the genomics and tumor microenvironment of breast mucoepidermoid carcinoma and proposed our hypothesis that although MECs arising in the breast resemble their salivary gland counterparts phenotypically, our findings indicate that breast MECs probably resemble invasive breast carcinomas at the genetic level and immune cell infiltration levels. More cases and in deep research need to be done to further understand this rare carcinoma.

Analysis of MUC6 polymorphisms on the clinicopathologic characteristics of Asian patients with oral squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are generally associated with tobacco consumption, alcohol abuse or both. Mucins (MUCs) are high-molecular-weight glycoproteins produced by many epithelial tissues. Many studies have indicated that MUCs play an important role in cancer metastasis. MUC6 expression has been observed in gastric and oncocytic phenotypes and plays an important role during cancer progression. We found that levels of MUC6 are lower in Asian HNCC patients and affect the disease-free survival of HNCC patients. Next, we investigated the combined effect of MUC6 polymorphisms and exposure to environmental carcinogens on the susceptibility to and clinicopathological characteristics of HNCC. Three single-nucleotide polymorphisms (SNPs) of MUC6 (rs7481521, rs6597947 and rs61869016) were analysed using real-time PCR. After adjusting for other co-variants, we found that carrying a CC genotype at MUC6 rs6597947 led to a lower risk of developing oral squamous cell carcinoma (OSCC) than wild-type carriers among non-betel-quid chewers. Moreover, male oral cancer patients who carried the AA + CC genotype at MUC6 rs6597947 had a lower risk of lymph node metastasis than other genotypes, suggesting a significant functional compromise and decompensated disease. Therefore, our findings suggest that genetic variations in MUC6 may correlate to OSCC and indicate the progression in OSCC patients.

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.

The Development of Vaccines from Synthetic Tumor-Associated Mucin Glycopeptides and their Glycosylation-Dependent Immune Response

Tumor-associated carbohydrate antigens are overexpressed as altered-self in most common epithelial cancers. Their glycosylation patterns differ from those of healthy cells, functioning as an ID for cancer cells. Scientists have been developing anti-cancer vaccines based on mucin glycopeptides, yet the interplay of delivery system, adjuvant and tumor associated MUC epitopes in the induced immune response is not well understood. The current state of the art suggests that the identity, abundancy and location of the glycans on the MUC backbone are all key parameters in the cellular and humoral response. This review shares lessons learned by us in over two decades of research in glycopeptide vaccines. By bridging synthetic chemistry and immunology, we discuss efforts in designing synthetic MUC1/4/16 vaccines and focus on the role of glycosylation patterns. We provide a brief introduction into the mechanisms of the immune system and aim to promote the development of cancer subunit vaccines.

HER2 Positivity in Histological Subtypes of Salivary Gland Carcinoma: A Systematic Review and Meta-Analysis

Background

HER2 aberrations in salivary gland carcinomas (SGC) as well as benefit of HER2 directed therapy have been reported in small studies. However, reliable estimates of the prevalence of HER2 positivity in SGC and its various histological subtypes are lacking.

Objective

To assess the prevalence of HER2 positivity in histological subtypes of salivary gland carcinomas (SGC).

Methods

Studies were identified by a systematic review of the literature. Data on in situ hybridization (ISH) and immunohistochemistry (IHC) were extracted to derive pooled prevalence estimates calculated by a random effects model. Characteristics of the studies were extracted for subgroup analysis.

Results

Fifty studies including 3372 patients were identified, providing data on sixteen histological subtypes. Based on the meta-analysis, the estimated prevalence of HER2 positivity were 43% (95% CI: 36% – 51%) in salivary duct carcinoma (SDC), 39% (95% CI: 32% – 45%) in carcinoma ex pleomorphic adenoma (CEP), 17% (95% CI: 7.5% – 33%) in squamous cell carcinoma (SCC), 13% (95% CI: 7.6% – 21%) in adenocarcinoma NOS (ADC), 6.7% (95% CI: 0.17%-32%) in poorly differentiated carcinoma, 5.5% (95% CI: 2.9% – 9.6%) in mucoepidermoid carcinoma, 4.3% (95% CI: 1.4% – 13%) in myoepithelial carcinoma, 1.8% (95% CI: 0.04%-9.6%) in epithelial-myoepithelial carcinoma, 0.45% (95% CI: 0.0097% – 18%) in acinic cell carcinoma and 0.15% (0.037% – 5.4%) in adenoid cystic carcinoma. Estimates for five additional subtypes were assessed.

Conclusion

Prevalence of HER 2 positivity in SGC varies greatly based on histological subtype, with SDC, CEP, SCC, and ADC displaying the highest rates.

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.

Prognostic and clinical implications of c-erbB-2 expression in patients with oral cancer: A meta-analysis

BACKGROUND

Recently, many studies have suggested that the aberrant expression of c-erbB-2 existed in oral cancer (OC) patients and had a correlation with poor clinical features across OC patients. Considering the inconsistent results among published articles, we performed the meta-analysis to assess the prognostic and clinical effect of c-erbB-2 expression on oral tumors.

METHODS

Web of Science, Embase, and PubMed were retrieved to acquire relevant publications based on selection criteria, up to February 8, 2020. Pooled odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) were applied to evaluate the associations between c-erbB-2 expression and overall survival (OS), disease specific survival, disease-free survival as well as clinicopathology of OC.

RESULTS

A total of 30 literatures with 1499 patients for survival of OC were enrolled in this meta-analysis. The results indicated that c-erbB-2 overexpression was significantly associated with poor OS (HR = 2.40, 95% CI = 1.53-2.55, P < .05), disease specific survival (HR = 2.60, 95% CI = 1.11-4.10, P < .05) and disease-free survival (HR = 2.22, 95% CI = 1.46-2.99, P < .05). Subgroup analysis based on race showed that the significant prognostic value of c-erbB-2 in OC was found both in Caucasians and Asians (OS of Caucasians, HR = 2.90, 95% CI = 1.50-4.31, P < .05; OS of Asians, HR = 1.90, 95% CI = 1.27-2.53, P < .05). Moreover, OC patients with enhanced c-erbB-2 expression were prone to male (OR = 1.97, 95% CI = 1.22-3.19, P < .05), advanced TNM stage (OR = 1.84, 95% CI = 1.17-2.88, P < .05), lymph node metastasis (OR = 2.23, 95% CI = 1.47-3.36, P < .05) and advanced grade (OR = 1.98, 95% CI = 1.30-3.01, P < .05), but not associated with distant metastasis (OR = 1.65, 95% CI = 0.98-3.04, P > .05).

CONCLUSIONS

c-erbB-2 may be a potential indicator in the prediction of prognosis and clinicopathological features in OC patients.

Systemic therapy for metastatic salivary gland tumors—challenges and novel concepts

Salivary gland cancers (SGC) are a rare and heterogeneous group of malignancies. Most frequently tumors arise in the parotid gland. The most common histologic subtypes are adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Rare subtypes include salivary ductal carcinoma (SDC), mammary analogue secretory carcinoma (MASC) and adenocarcinoma not other specified (AC NOS). For locally advanced or metastatic disease, chemotherapy has been the mainstay of therapy. The course of disease differs markedly between the subtypes, especially ACC usually presents as slowly progressing disease. Due to the rarity of these tumors only small phase I/II studies exist, which report efficacy of cytotoxic regimens in advanced SGC. However, due to advances in the understanding of tumor biology and molecular testing, drugable genetic changes like androgen receptor (AR) status, HER2/neu overexpression and neurotrophic tyrosine receptor kinase (NTRK) gene fusion have evolved as potential therapy targets in subsets of SGC. Consequently therapy with androgen receptor blockade (ARB) can be offered to patients with AR expressing tumors. Anti-HER2 therapy with trastzumab is an option for the treatment of tumors with overexpression of HER2/neu and finally NTRAK inhibitors can be used for tumors harboring a NTRK gene fusion. Taken together, due to the small number of patients, data from large phase III studies for the treatment of SGC are missing. However, promising targeted therapy approaches have been recently undertaken.

Assessing the prognostic significance of MUC4β in mucoepidermoid carcinoma of the salivary glands: An immunohistochemical study

Objectives

– Routine histopathological grading for salivary gland mucoepidermoid carcinoma (MEC) have failed to prognosticate these tumors, resulting in poor post-surgical outcomes. In developing countries, the lack of technologically advanced infrastructure curtails, efficient treatment modalities. This study aimed at determining if MUC4β can characterize salivary gland MEC and serve as a practical and inexpensive method to prognosticate salivary gland MEC.

Materials and methods

– Fifteen cases of archived paraffin embedded tissue blocks of mucoepidermoid carcinomas were reassessed for histopathological grading using Healey's system, modified by Batsakis and Luna and immunohistochemically evaluated for expression of MUC4β. Statistical analysis (Kappa statistics and Spearman's rho correlation coefficient) was performed to assess inter-observer reproducibility and to correlate the expression of MUC4β with the histopathological grade of the tumor.

Results

MUC4β expression is related to tumor differentiation in an inverse relationship. Two cases of high grade MEC were the exception to this rule.

Conclusion

Our study revealed that MUC4β alone cannot serve as a reliable prognostic marker due to its divergent tumor suppressor and oncogenic pathway. The role of MUC4β needs further evaluation and research so as to potentiate therapeutics depending upon its context dependent function, as a cancer marker or an oncogenic factor.

Second-Line Treatment of HER2-Positive Salivary Gland Tumor: Ado-Trastuzumab Emtansine (T-DM1) after Progression on Trastuzumab

Patients with salivary duct cancer (SDC) and HER2 overexpression could receive trastuzumab in combination with chemotherapy for metastatic disease. No standard treatment exists for patients with HER2-positive metastatic SDC after progression. We report an excellent patient response to second-line treatment with T-DM1 after progression on paclitaxel plus trastuzumab.

MUC4 immunohistochemistry is useful in distinguishing epithelioid mesothelioma from adenocarcinoma and squamous cell carcinoma of the lung

The differential diagnosis of epithelioid mesothelioma from lung adenocarcinoma and squamous cell carcinoma requires the positive and negative immunohistochemical markers of mesothelioma. The IMIG guideline has suggested the use of Calretinin, D2–40, WT1, and CK5/6 as mesothelial markers, TTF-1, Napsin-A, Claudin 4, CEA as lung adenocarcinoma markers p40, p63, CK5/6, MOC-31 as squamous cell markers. However, use of other immunohistochemical markers is still necessary. We evaluated 65 epithelioid mesotheliomas, 60 adenocarcinomas, and 57 squamous cell carcinomas of the lung for MUC4 expression by immunohistochemistry and compared with the previously known immunohistochemical markers. MUC4 expression was not found in any of 65 cases of epithelioid mesothelioma. In contrast, MUC4 expression was observed in 50/60(83.3%) cases of lung adenocarcinoma and 50/56(89.3%) cases of lung squamous cell carcinoma. The negative MUC4 expression showed 100% sensitivity, 86.2% specificity and accuracy rate of 91.2% to differentiate epithelioid mesothelioma from lung carcinoma. The sensitivity, specificity, and accuracy of MUC4 are comparable to that of previously known markers of lung adenocarcinoma and squamous cell carcinoma, namely CEA, Claudin 4 and better than that of MOC-31. In conclusion, MUC4 immunohistochemistry is useful for differentiation of epithelioid mesothelioma from lung carcinoma, either adenocarcinoma or squamous cell carcinoma.

Prognostic and clinicopathological significance of MUC expression in head and neck cancer: a systematic review and meta-analysis

The prognostic value of mucins expression in patients with head and neck cancer (HNC) remains controversial. To address this, a meta-analysis was performed to systematically evaluate prognostic significance of mucins expression in HNC. Electronic and manual searches were performed and a total of 20 studies including 2046 patients were selected for the final analysis. Increased mucins expression was associated with unfavorable overall survival in HNC patients (HR=1.83, 95% CI: 1.43-2.33, p=0.000). Mucins overexpression was also in correlation with more advanced TNM stage (RR=0.84, 95% CI: 0.73-0.97, p=0.017), higher risk of lymph node metastasis (RR=0.69, 95% CI: 0.57-0.84, p=0.000) and deeper invasion (RR=0.58, 95% CI: 0.44-0.76, p=0.000). These results suggested that elevated mucins expression was significantly associated with worse prognosis and more detrimental clinicopathological outcomes, revealing the promising potential of mucins as biomarkers for HNC management.

Significant and durable clinical benefit from trastuzumab in 2 patients with HER2-amplified salivary gland cancer and a review of the literature

BACKGROUND

Salivary ductal carcinoma and carcinoma ex pleomorphic adenoma (CEPA) are aggressive salivary gland cancers with poor prognosis. The standard of care is resection with or without radiotherapy, and there are no established systemic therapy options.

METHODS

We describe 1 patient with metastatic CEPA and 1 patient with metastatic recurrent salivary duct carcinoma whose tumors were evaluated by comprehensive genomic profiling. Testing identified human epidermal growth factor receptor 2 (HER2) amplification in both patients, and an additional activating HER2 mutation in the CEPA case.

RESULTS

Both patients were treated with the HER2-targeting monoclonal antibody trastuzumab (herceptin) plus chemotherapy and experienced rapid responses. Subsequently, both patients were given single-agent maintenance trastuzumab and continue to experience durable disease control.

CONCLUSION

Given the poor prognosis for salivary gland cancers and the limited treatment options upon recurrence or metastasis, patients should be tested for all classes of HER2 alterations. In cases with HER2 overexpression or activation, targeted therapies, such as trastuzumab are promising. © 2016 Wiley Periodicals, Inc. Head Neck 39: E40-E44, 2017.

Expression of MUC4 mucin is observed mainly in the intestinal type of intraductal papillary mucinous neoplasm of the pancreas

OBJECTIVES

This study aimed to examine expression profile of MUC4 in intraductal papillary mucinous neoplasm of the pancreas (IPMN).

METHODS

We performed immunohistochemistry (IHC) of MUC4 in 142 IPMNs, with evaluation of the specificity of 2 anti-MUC4 monoclonal antibodies, 8G7 and 1G8, in cancer cell lines.

RESULTS

Monoclonal antibody 8G7 showed a clear immunoreactivity, whereas MAb 1G8 did not show any immunoreactivity, in the Western blotting and IHC for human pancreatic carcinoma cell lines expressing MUC4 messenger RNA. However, IHC signals detected by both monoclonal antibodies were observed in the tissue specimens. The expression rates of MUC4/8G7 detected by MAb 8G7 and MUC4/1G8 detected by MAb 1G8 in the intestinal-type IPMNs were significantly higher than those in the gastric-type IPMNs. In the intestinal-type IPMNs, MUC4/8G7 was expressed mainly in the cytoplasm of the neoplastic cells, whereas MUC4/1G8 was expressed mainly at the cell apexes. Even in the gastric-type IPMNs with rare MUC4 expression in the low-grade dysplasia, both MUC4 expression rates increased when dysplasia advanced.

CONCLUSIONS

A significantly higher expression of MUC4 in intestinal-type IPMNs than in gastric-type IPMNs will be one of the biomarkers to discriminate between the intestinal-type IPMNs with high malignancy potential from gastric-type IPMNs with low malignancy potential.

MUC4 as a diagnostic marker in cancer

BACKGROUND

Mucins are high molecular mass glycoproteins whose role in diagnosis, prognosis and therapy is being increasingly recognized owing to their altered expression in a variety of carcinomas. MUC4, a membrane-bound mucin encoded by a gene located on chromosome locus 3q29, is aberrantly expressed in several cancers including those of the bile duct, breast, colon, esophagus, ovary, lung, prostate, stomach and pancreas.

OBJECTIVE

This review considers the potential use of the MUC4 expression pattern in the diagnosis and prognosis of various cancers.

RESULTS/CONCLUSION

MUC4 expression is a specific marker of epithelial tumors and its expression correlates positively with the degree of differentiation in several cancers. Importantly, MUC4 has emerged as a specific marker of dysplasia, being expressed in the earliest dysplastic lesions preceding several malignancies, including lethal pancreatic cancer. The presence of MUC4-specific antibodies in the serum and of the transcript in peripheral blood mononuclear cells of cancer patients raises the possibility of it emerging as a new diagnostic biomarker for bedside application in high-risk individuals and those with established cancer.

MUC4 and MUC1 expression in adenocarcinoma of the stomach correlates with vessel invasion and lymph node metastasis: an immunohistochemical study of early gastric cancer

We have previously reported that MUC4 expression is a poor prognostic factor in various carcinomas. Our previous study also showed that MUC1 expression in gastric cancers, including the early and advanced stages is a poor prognostic factor. In the present study, the expression profiles of MUC4 and MUC1 were examined by immunohistochemistry (IHC) using two anti-MUC4 monoclonal antibodies (MAbs), 8G7 and 1G8, and anti-MUC1 MAb DF3 in 104 gastrectomy specimens of early gastric adenocarcinoma with submucosal invasion (pT1b2), including 197 histological subtype lesions. Before the IHC study of the human specimens, we evaluated the specificity of the two MAbs by Western blotting and IHC of two MUC4 mRNA expressing gastric cancer cell lines. MAb 8G7 reacted clearly, whereas MAb 1G8 did not show any reactivity, in either Western blotting or IHC. In the IHC of the gastric cancers, the expression rates of MUC4/8G7 detected by MAb 8G7, MUC4/1G8 detected by MAb 1G8 and MUC1/DF3 detected by MAb DF3 in well differentiated types (70%, 38/54; 67%, 36/54; 52%, 28/54) were significantly higher than those in poorly differentiated types (18%, 10/55; 36%, 20/55; 13%, 7/55) (P<0.0001; P = 0.0021; P<0.0001), respectively. The MUC4/8G7 expression was related with lymphatic invasion (r = 0.304, P = 0.033). On the other hand, the MUC4/1G8 expression was related with lymphatic invasion (r = 0.395, P = 0.001) and lymph node metastasis (r = 0.296, P = 0.045). The MUC1/DF3 expression was related with lymphatic invasion (r = 0.357, P = 0.032) and venous invasion (r = 0.377, P = 0.024). In conclusion, the expression of MUC4 as well as MUC1 in early gastric cancers is a useful marker to predict poor prognostic factors related with vessel invasion.

Expression of MUC1 and MUC4 in gallbladder adenocarcinoma

Background

Recent reports have indicated that overexpression of mucin (MUC) 1 and/or MUC4 correlates with the occurrence and progression of extra-hepatobiliary malignancy. In this study, we investigated the expression of MUC1 and MUC4 and their prognostic significance in gallbladder adenocarcinoma.

Methods

We examined 54 surgical gallbladder adenocarcinoma samples by immunohistochemistry for MUC1 and MUC4 expression. Staining was evaluated as a sum score of extent and intensity, dividing the samples into low and high expression groups.

Results

The low expression group for both MUC1 and MUC4 was 10 samples (18.5%), and the high expression group was 44 samples (81.5%). High MUC1 expression was significantly correlated with more differentiated tumors (p=0.033), whereas high expression of MUC4 correlated with negative nodal status (p=0.012). Other pathological features were not correlated with MUC expression. Multivariate cox regression analysis showed that neither MUC1 nor MUC4 expression correlated with survival.

Conclusions

Although there were some correlations found, a prognostic role for either MUC1 or MUC4 expression in gallbladder carcinoma was not identified in this study. Further investigation is required.

Systemic therapy in the management of metastatic or advanced salivary gland cancers

Salivary gland cancers are very rare tumors. They are characterized by a histologic heterogeneity and a poor outcome. According to this rarity, few prospective data are available to date. No standard recommendations could be held for the use of systemic therapy in these tumors. Several case reports and small studies have investigated the contribution of different agents of chemotherapy. With the extension of molecular biology approach in oncology several signaling pathways have been discovered in different cancers including salivary gland cancers; thus a number of targeted therapies have been investigated. This paper reviewed exhaustively the studies investigating the role of systemic therapies (chemotherapy, targeted therapy, hormone therapy) in salivary gland cancers.

Prognostic significance of membrane-associated mucins 1 and 4 in gastric adenocarcinoma

Aberrant expression of mucins is likely associated with cancer biology as alterations in the expression and/or glycosylation patterns of various mucins have been noted. Expression of the mucin family in gastric cancers has been reported in numerous studies, but the results are conflicting. Therefore, we investigated the potential use of mucin (MUC)1 and 4 as prognostic markers in gastric cancer according to histological subtype. Three-hundred and sixty-five gastric adenocarcinoma patients who underwent surgical resection were selected for this study. Among the 365 gastric cancer samples tested here, 34% consisted of early gastric cancer and 66% were advanced. In terms of location, 68.7% of the cohort had intestinal-type cancer and 30.7% had diffuse-type. We constructed tissue microarrays with formalin-fixed paraffin-embedded blocks of gastric cancer and these micro-arrays were evaluated for phenotypic expression of MUC1/4 using monoclonal antibodies. Two-hundred and ninety-two patients (92.7%) were positive for MUC1 and 216 (60.5%) were positive for MUC4. MUC1 expression was not correlated with any other clinicopathological variables such as age, gender, depth of invasion, lymph node metastasis, Lauren classification or recurrence. However, loss of MUC4 expression was significantly correlated with recurrence (p=0.033). MUC4 expression was also significantly correlated with better disease-free survival (p=0.049) and particularly in the intestinal-type (p=0.018). Our present findings demonstrated that loss of MUC4 expression can be used as a prognostic marker in gastric cancer. Loss of MUC4 expression is a prognostic indicator of increased recurrence and poor disease-free survival in patients with gastric cancer.

Systemic therapy in the management of metastatic or advanced salivary gland cancers

Salivary gland cancers are very rare tumors. They are characterized by a histologic heterogeneity and a poor outcome. According to this rarity, few prospective data are available to date. No standard recommendations could be held for the use of systemic therapy in these tumors. Several case reports and small studies have investigated the contribution of different agents of chemotherapy. With the extension of molecular biology approach in oncology several signaling pathways have been discovered in different cancers including salivary gland cancers; thus a number of targeted therapies have been investigated. This paper reviewed exhaustively the studies investigating the role of systemic therapies (chemotherapy, targeted therapy, hormone therapy) in salivary gland cancers.

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.

Prognostic value of mucin 4 expression in colorectal adenocarcinomas

BACKGROUND

Mucin 4 (MUC4) is aberrantly expressed in colorectal adenocarcinomas (CRCs) but its prognostic value is unknown.

METHODS

Archival tissue specimens collected from 132 CRC patients who underwent surgical resection without presurgery or postsurgery therapy were evaluated for expression of MUC4 by using a mouse monoclonal antibody and horseradish peroxidase. MUC4 expression levels were correlated with clinicopathologic features and patient survival. Survival was estimated by both univariate Kaplan-Meier and multivariate Cox regression methods.

RESULTS

In both normal colonic epithelium and CRCs, MUC4 staining was localized primarily in the cytoplasm. The optimal immunostaining cutoff value (>or=75% positive cells and an immunostaining score>or=2.0), which was derived by using the bootstrap method, was used to categorize CRCs into groups of high expression (33 of 132 patients; 25%) or low expression (99 of 132 patients; 75%). Patients who had early stage tumors (stages I and II) with high MUC4 expression had a shorter disease-specific survival (log-rank; P=.007) than patients who had with low expression. Patients who had advanced-stage CRCs (stages III and IV) did not demonstrate such a difference (log-rank; P=.108). Multivariate regression models that were generated separately for patients with early stage and advanced-stage CRC confirmed that increased expression of MUC4 was an independent indicator of a poor prognosis only for patients who had early stage CRCs (hazard ratio, 3.77; 95% confidence interval, 1.46-9.73).

CONCLUSIONS

The current results indicated that increased MUC4 expression is a predictor of poor survival in CRC, specifically for patients who have early stage tumors.

The membrane-bound mucins: From cell signalling to transcriptional regulation and expression in epithelial cancers

The membrane-bound mucins belong to an ever-increasing family of O-glycoproteins. Based on their structure and localization at the cell surface they are thought to play important biological roles in cell-cell and cell-matrix interactions, in cell signalling and in modulating biological properties of cancer cells. Among them, MUC1 and MUC4 mucins are best characterized. Their altered expression in cancer (overexpression in the respiratory, gastro-intestinal, urogenital and hepato-biliary tracts) indicates an important role for these membrane-bound mucins in tumour progression, metastasis, cancer cell resistance to chemotherapeutics drugs and as specific markers of epithelial cancer cells. Some mechanisms responsible for MUC1 and MUC4 role in tumour cell properties have been deciphered recently. However, much remains to be done in order to understand the molecular mechanisms and signalling pathways that control the expression of membrane-bound mucins during the different steps of tumour progression toward adenocarcinoma and evaluate their potential as prognostic/diagnostic markers and as therapeutic tools. In this review we focus on the molecular mechanisms and signalling pathways known to control the expression of membrane-bound mucins in cancer. We will discuss the mechanisms of regulation at the promoter level (including genetic and epigenetic modifications) that may be responsible for the mucin altered pattern of expression in epithelial cancers.

MUC4 involvement in ErbB2/ErbB3 phosphorylation and signaling in response to airway cell mechanical injury

The receptor tyrosine kinases ErbB2 and ErbB3 are phosphorylated in response to injury of the airway epithelium. Since we have shown that the membrane mucin MUC4 can act as a ligand/modulator for ErbB2, affecting its localization in polarized epithelial cells and its phosphorylation, we questioned whether Muc4 was involved, along with ErbB2 and ErbB3, in the damage response of airway epithelia. To test this hypothesis, we first examined the localization of MUC4 in human airway samples. Both immunocytochemistry and immunofluorescence showed a co-localization of MUC4 and ErbB2 at the airway luminal surface. Sequential immunoprecipitation and immunoblotting from airway cells demonstrated that the MUC4 and ErbB2 are present as a complex in airway epithelial cells. To assess the participation of MUC4 in the damage response, cultures of NCI-H292 or airway cells were scratch-wounded, then analyzed for association of phospho-ErbB2 and -ErbB3 with MUC4 by sequential immunoprecipitation and immunoblotting. Wounded cultures exhibited increased phosphorylation of both receptors in complex with MUC4. Scratch wounding also increased activation of the downstream pathway through Akt, as predicted from our previous studies on Muc4 effects on ErbB2 and ErbB3. The participation of MUC4 in the phosphorylation response was also indicated by siRNA repression of MUC4 expression, which resulted in diminution of the phosphorylation of ErbB2 and ErbB3. These studies provide a new model for the airway epithelial damage response, in which the MUC4-ErbB2 complex is a key element in the sensor mechanism and phosphorylation of the receptors.

Cancer mucoépidermoïde des glandes salivaires: signification pronostique des marqueurs tumoraux

INTRODUCTION

Mucoepidermoid carcinoma is one of the most frequent malignant lesions of salivary glands. The treatment is based on clinical, paraclinical and histological data. Several studies on the prognostic value of molecular markers for these cancers were made with contradictory results. The aim of this retrospective study was to analyze the prognostic value of molecular markers of salivary gland mucoepidermoid carcinoma.

MATERIAL AND METHODS

Sixteen patients were treated for mucoepidermoid carcinoma of principal and/or accessory salivary glands between 1994 and 2003. An immunohistochemical study of archive specimen was performed. Nine markers were specifically studied: 4 proteins/oncoproteins (p53, bcl2, c-erb-B2 and cd117), 2 markers of proliferation (PCNA and Ki67), 1 growing factor receptor (EGFR), 1 epithelial adhesion molecule (E-cadherin), and 1 angiogenic cytokine (PDGF).

RESULTS

Nine men and 7 women were included, with a mean age of 43.7 years (14-80). The mean diameter of tumors was 3.1 mm (1-14), and the parotid gland was the most frequent location. The mean global survival rate was 57.3 months with a median of 55 months. The 2 to 5 years survival expectation rate were 82.5% and 46.4% respectively. The mean survival rate for women was superior to that of men (P=0.043). The expression of p53 and the high expression rate of EFGR were bad prognostic factors (respectively P=0.049 and P=0.012). The expression of PCNA was linked to the location (mainly the salivary gland) and to the diameter of the tumor (respectively P=0.037 and P=0.029). The degree of EFGR positivity and the histological grade were linked (P=0.027).

DISCUSSION

The strong expression of EGFR was statistically linked to the histological tumor grade. The degree of PCNA positivity seemed to be associated to the preferential location in the main salivary glands and to the diameter of the tumor. The strong expression of p53 and EGFR were bad prognostic factors. These retrospective results need to be confirmed by prospective randomized and larger studies. EGFR and p53 were significant negative prognostic factors. EGFR was highly correlated to the histological grade, making it an interesting target for further investigation.

Structure, evolution, and biology of the MUC4 mucin

Mucins are high-molecular-weight glycoproteins and are implicated in diverse biological functions. MUC4, a member of transmembrane mucin family, is expressed in airway epithelial cells and body fluids like saliva, tear film, ear fluid, and breast milk. In addition to its normal expression, an aberrant expression of MUC4 has been reported in a variety of carcinomas. Among various potential domains of MUC4, epidermal growth factor (EGF) -like domains are hypothesized to interact with and activate the ErbB2 receptors, suggesting an intramembrane-growth factor function for MUC4. The heavily glycosylated tandem repeat domain provides the structural rigidity to the extended extracellular region. MUC4, by virtue of its extended structure, serves as a barrier for some cell-cell and cell-extracellular matrix interactions and as a potential reservoir for certain growth factors. An intricate relationship between MUC4 and growth factor signaling is also reflected in the transcriptional regulation of MUC4. The MUC4 promoter has binding sites for different transcription factors, which are responsible for the regulation of its expression in different tissues. The interferon-gamma, retinoic acid, and transforming growth factor-beta signaling pathways regulate MUC4 expression in a partially interdependent manner. Taken together, all of these features of MUC4 strongly support its role as a potential candidate for diagnostic and therapeutic applications in cancer and other diseases.

beta-Catenin nuclear accumulation in head and neck mucoepidermoid carcinoma: its role in cyclin D1 overexpression and tumor progression

BACKGROUND

Nuclear/cytoplasmic accumulation of beta-catenin is mainly regulated by its degradation, which is initiated by interaction with adenomatous polyposis coli (APC) protein. Accumulation of beta-catenin activates the transcription of 1 of the target oncogenic genes, cyclin D1, in the Wnt/Wingless pathway. The role of beta-catenin and cyclin D1 in this pathway has not been previously studied in head and neck mucoepidermoid carcinoma (MEC). This study investigates abnormalities of beta-catenin and the APC gene in MEC and correlates the patterns of cyclin D1 overexpression and nuclear/cytoplasmic accumulation of beta-catenin with the clinical outcome.

METHODS

Mutations of the beta-catenin and APC genes, as well as overexpression of cyclin D1, were investigated by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) in tissue samples from 44 cases of MEC. In addition, we employed differential PCR method to detect amplification of the cyclin D1 gene. Furthermore, the overexpression of cyclin D1 and nuclear/cytoplasmic accumulation of beta-catenin was examined by immunohistochemistry, and any correlation with clinicopathologic parameters was evaluated.

RESULTS

Nuclear/cytoplasmic accumulation of beta-catenin was observed in 6 of 44 MEC cases (13.6%), 5 of which were high-grade MEC, while the other 1 case was intermediate-grade tumor. Mutational analysis of exon 3 of the beta-catenin gene revealed that 4 of 26 cases (15.4%) contained point mutations (3 in codon 32, GAC [Asp] to GGC [Gly]; 1 in codon 42, ACA [Thr] to ATA [Ile]), and all these 4 cases showed beta-catenin accumulation immunohistochemically. The nuclear/cytoplasmic accumulation of beta-catenin was significantly correlated with the adverse outcome of patients (p = .011). Two APC gene alterations were detected in 2 cases of low-grade MEC, where there was no beta-catenin nuclear accumulation. Amplification of the cyclin D1 gene was observed in 10 of 26 cases (38.5%). Cyclin D1 overexpression was recognized in 19 of 44 cases (43.2%) and was significantly correlated with beta-catenin accumulation (p = .003).

CONCLUSIONS

These findings suggest that beta-catenin, which, in cooperation with cyclin D1, plays crucial role in the Wnt-signaling pathway, may also contribute to the adverse outcome and high-grade tumor staging of MEC.

MUC4 expression in non-small cell lung carcinomas: relationship to tumor histology and patient survival

CONTEXT

Mucin 4 (MUC4) is a high-molecular-weight membrane-bound glycoprotein that is expressed in the foregut before epithelial differentiation. It is found in normal adult airway epithelium, non-small cell lung carcinoma (NSCLC) and in other human malignancies independent of mucus secretion. Although its tissue distribution has been studied, its utility in predicting prognosis in NSCLC is unknown.

OBJECTIVE

To evaluate the relationship between MUC4 overexpression and long-term survival in patients with NSCLC.

DESIGN

Immunohistochemical staining for MUC4 was performed on formalin-fixed, paraffin-embedded tissue samples from 343 cases of NSCLC arranged in a high-density tissue microarray. Information about long-term survival and tumor stage was collected for all patients. Semiquantitative assessment of MUC4 staining was correlated with survival (Kaplan-Meier analysis).

RESULTS

MUC4 was frequently expressed in adenocarcinomas (151/187 [81%]), squamous cell carcinomas (69/ 88 [78%]), adenosquamous carcinomas (6/8 [75%]), and large cell carcinomas (33/60 [55%]). High levels of expression (combined score, 2+/3+) for MUC4 were more characteristic of adenocarcinomas (126/187 [68%]) and adenosquamous carcinomas (6/8 [75%]) than of squamous cell carcinomas (46/88 [52%]) and large cell carcinomas (17/60 [28%]) (P < .001). In patients with stage I and II adenocarcinoma, there was a trend toward longer patient survival with higher levels of MUC4 immunoreactivity compared with lower levels (P = .11).

CONCLUSION

MUC4 expression is common in pulmonary adenocarcinomas and may indicate a more favorable prognosis in early-stage adenocarcinomas.

MUC4 expression and its relation to ErbB2 expression, apoptosis, proliferation, differentiation, and tumor stage in non-small cell lung cancer (NSCLC)

There is a peptide sequence homology between the gene product of human MUC4 and rat Muc4/sialomucin complex (SMC). Each contains a transmembrane subunit with two epidermal growth factor (EGF)-like domains that act as ligand for ErbB2. MUC4 and ErbB2 mediate intracellular signaling pathways that are linked to repression of apoptosis and either to proliferation or to differentiation of tumor cells. This study investigates the expression of human MUC4 in neoplastic and corresponding non-neoplastic tissues, and the relation of MUC4 expression in neoplastic tissues to ErbB2 expression, apoptosis, proliferation, differentiation, and tumor stage in a series of 100 non-small cell lung carcinomas (NSCLCs). MUC4 and ErbB2 expressions and cell proliferation (PCNA) were shown using immunohistochemistry. Apoptotic index (AI) and tumor differentiation were determined by morphologic criteria. All the non-neoplastic bronchial tissues and 85% of NSCLCs showed MUC4 expression. MUC4 expression was found to be higher in neoplastic than in non-neoplastic tissues (Yates correction p: 0.0006). MUC4 expression was inversely correlated with AI (p=0.0002) and was correlated with ErbB2 expression (p=0.022), but not with PCNA counts and tumor stage. Our results indirectly suggest that MUC4, in association with ErbB-2, might be involved in the repression of apoptosis and differentiation rather than proliferation in tumor cells of NSCLCs.

Aberrant expression of transmembrane mucins, MUC1 and MUC4, in human prostate carcinomas

BACKGROUND

Mucins are considered important markers for early diagnosis and targeted therapy due to their aberrant and unique expression pattern during malignant progression of carcinomas. Recent findings have provided substantial evidence for the involvement of transmembrane mucins, MUC1 and MUC4, in altered cell signaling, tumor growth, and metastasis.

METHODS

Immunohistochemical analyses were performed on prostate tumor tissues for expression profiling of the two transmembrane mucins, MUC1 and MUC4. In cancer cell lines, the expression was studied by RT-PCR and immunoblot analyses. Cells were treated with DNA-methylase and histone-deacetylase inhibitors to examine the implication of epigenetic mechanism(s) in MUC4 regulation.

RESULTS

The expression of MUC4 was significantly down regulated in prostate cancer tissues (n=38, P=0.0026) compared to normal/benign prostatic hyperplastic regions. A faint to moderate staining was observed in 26.3% cases of cancer, while 84.2% cases of adjacent normal were positive for MUC4 with moderate to strong staining in most cases. Similar observations were made in immortalized normal prostate epithelial and cancer cell lines. MUC1 also showed a reduced expression in prostate tumor tissues; however, its expression was comparable in all normal prostate epithelial and cancer cell lines. Interestingly, we also found that epigenetic mechanism(s) might be implicated in MUC4 gene silencing.

CONCLUSIONS

Our data suggest that MUC4 downregulation may be of significance for diagnostic applications in prostate cancer.

MUC1, MUC2, MUC4, and MUC5AC expression in salivary gland mucoepidermoid carcinoma: diagnostic and prognostic implications

We determined whether immunostaining for mucins could provide a better characterization of salivary gland mucoepidermoid carcinoma (MEC). We investigated 63 MECs by immunohistochemistry for MUC1, MUC2, MUC4, and MUC5AC. Mucin expressing cell types and labeling patterns were recorded. The results were compared with microscopic grade, tumor-associated lymphoid infiltrate, mucin expression in surrounding salivary glands, clinical features, and outcome. MUC1 and MUC4 labeled the apical membrane of glandular tumor cells and the entire membrane of intermediate, clear, and epidermoid tumor cells. MUC2 and MUC5AC were expressed in the cytoplasm of glandular, mucous, and intermediate tumor cells. In contrast to MUC1, MUC4 expression decreased with tumor grade (P < 0.01). Unlike MUC2, MUC5AC was expressed in more than 50% of high-grade tumors, including 2 cases that were not stained with Alcian blue. MUC1 and MUC5AC were associated with tumor-associated lymphoid infiltrates (P < 0.05), but not with tumor-associated lymphoid follicles. The proportions of tumors expressing mucins were 71% for MUC1, 21% for MUC2, 79% for MUC4, and 68% for MUC5AC. MUC1 and MUC5AC were more frequently expressed in tumors than in surrounding glands (P < 0.0001). MUC1 expression correlated with shorter progression-free survival (P < 0.05). In conclusion, mucin expression in MEC differs from that in salivary glands. Intermediate cells express MUC1 and MUC4 all along their cell surface and MUC2 and MUC5AC in their cytoplasm. Staining for MUC5AC in high-grade tumors can be helpful for distinguishing high-grade MEC from squamous cell carcinoma. While MUC4 is related to tumor differentiation, MUC1 expression indicates a worse prognosis.

Expression of Membrane-Bound Mucins (MUC1 and MUC4) and Secreted Mucins (MUC2, MUC5AC, MUC5B, MUC6 and MUC7) in Mucoepidermoid Carcinomas of Salivary Glands

Mucins are glycoproteins normally synthesized by a variety of secretory epithelial cells. The aim of this study was to investigate the expression of mucins (MUC1, MUC2, MUC4, MUC5AC, MUCB, MUC6, MUC7) in mucoepidermoid carcinomas, the most frequent malignant tumor of salivary glands. Forty mucoepidermoid carcinomas and twenty-two normal salivary glands were studied for these mucins by immunohistochemistry from formalin-fixed and paraffin-embedded material. Normal salivary glands frequently expressed MUC1 and MUC4, mainly in ductal cells; MUC5B and MUC7 stained mucous and serous acini respectively of submandibular and minor salivary glands; and MUC5AC and MUC2 were poorly detected in excretory ducts. All mucoepidermoid carcinomas expressed MUC1, and 38/40 tumors expressed MUC4. Both membrane-bound mucins stained membranes and cytoplasm of all cell types (epidermoid, intermediate, mucous, clear and columnar). MUC5AC and MUC5B stained glandular differentiated cells in most tumors (29/40 and 33/40 cases, respectively). MUC6 was positive in 13/40 tumors, and both MUC2 and MUC7 in only 2/40 tumors. The high expression of MUC1 was related to high histologic grades, high recurrence and metastasis rates and a shorter disease-free interval (P < 0.05). Conversely, MUC4 high expression was mainly related to low-grade tumors, lower recurrence rates and a longer disease-free interval (P < 0.05). In conclusion, mucoepidermoid carcinomas of salivary glands usually express MUC1, MUC4, MUC5AC and MUC5B; less frequently MUC6; and rarely MUC2 and MUC7. This mucin expression pattern can be useful for diagnostic purposes. Therefore, MUC1 expression is related to tumor progression and worse prognosis, whereas MUC4 expression is related to a better prognosis.

MUC4 and ErbB2 expression in squamous cell carcinoma of the upper aerodigestive tract: correlation with clinical outcomes

OBJECTIVES/HYPOTHESIS

Expression of the membrane mucin MUC4 has been associated with a variety of malignancies, including squamous cell carcinoma of the upper aerodigestive tract. MUC4 modulates cell signaling pathways as an intramembrane ligand of ErbB2. The hypotheses of the study were that MUC4 expression would correlate with ErbB2 expression and that MUC4 expression would correlate with clinical outcomes in squamous cell carcinoma of the upper aerodigestive tract.

STUDY DESIGN

Retrospective chart review was combined with immunohistochemical analysis of paraffin-embedded tumor specimens from patients treated with initial definitive surgical resection at an academic tertiary care medical center.

METHODS

MUC4 and ErbB2 receptor expression was localized by immunohistochemical studies using archival formalin-fixed and paraffin-embedded tissue. A limited number of fresh-frozen tissues were further analyzed by Western blot. Clinical outcomes and histopathological parameters were determined by retrospective chart review and correlated with immunohistochemical findings.

RESULTS

One hundred fifty-four patients were analyzed with a median follow-up of 12 months among 54 patients who died and 49 months among 100 surviving patients. Membrane expression of MUC4 and ErbB2 was seen in 12% and 13% of tumors, respectively. MUC4 expression was not correlated with pathological grade. A significant correlation was found between MUC4 expression and ErbB2 expression. Multivariate survival analyses revealed that patients whose tumors exhibited MUC4 membrane expression had statistically significant improvement in survival and longer time to recurrence compared with patients whose tumors did not express MUC4 as defined by immunohistochemical staining patterns. No correlations between ErbB2 expression and survival or recurrence were observed.

CONCLUSION

Patients with tumors that retain MUC4 expression exhibit improved survival and decreased recurrence in squamous cell carcinoma of the upper aerodigestive tract. Correlations between MUC4 expression patterns and ErbB2 expression are also observed, suggesting that MUC4-ErbB2 mediated cell signaling pathways may provide insights into this clinical result.