Prognostic significance of p27 and Ki-67 expression in mucoepidermoid carcinoma of the intraoral minor salivary gland

Mucoepidermoid carcinoma of the lower lip: A case report and review of literature

Mucoepidermoid carcinoma (MEC) is a rare salivary gland malignancy characterized by diverse cellular components. This case report presents a unique instance of low-grade MEC in a 28-year-old female, emphasizing the importance of accurate diagnosis and tailored management. The patient exhibited a painless, enlarging lower lip swelling over a year, with imaging suggestive of a fibrolipomatous lesion. Surgical excision was successfully performed, with subsequent histopathological analysis displaying mucinous cystic spaces, varied epithelial cell types and other characteristic features consistent with MEC. The case findings aligned with hallmark MEC features are seen in established literature, highlighting the significance of precise diagnosis and grading for appropriate management. This report contributes to the understanding of MEC's varied presentations and underscores the importance of thorough: histopathological examination, lower lip, mucoepidermoid carcinoma clinical evaluation, accurate histopathological analysis and interdisciplinary collaboration. The case highlights the value of considering MEC in younger patients, even with atypical presentations, and encourages ongoing exploration of diagnostic and therapeutic strategies to improve patient outcomes.

Perineural Invasion as Worsening Criterion for Salivary Gland Mucoepidermoid Carcinoma

Mucoepidermoid carcinomas (MECs) are a form of salivary gland malignancy. They are classified according to histological grade and perineural invasion (PNI). In another cancer subtypes, positive-PNI suggests increased poor prognosis; however, the role of isolated positive-PNI salivary gland MEC can still be better investigated as a risk factor. This study investigated whether isolated PNI is independently associated with poor outcomes. Retrospective study, cohort case-series, single-center hospital from 2009 to 2019. Patient demographics, primary tumor, intervention, and survival data are included. Univariate, multivariate, and Kaplan-Meier survival curve analyses were used for comparison.The study group consisted of 32 patients (15 PNI-positive tumors, and 17 PNI-negative tumors), all admitted for surgery. Univariate analysis showed differences in grade (p = 0.038), positive margins (p = 0.034), soft tissue invasion (p < 0.001), pathological stage (p = 0.014), recurrence (p = 0.015), distant metastasis (p = 0.015) and MEC related death (p = 0.015). The risk in PNI-positive patients to develop soft tissue invasion and positive surgical margins was OR = 8.57 and OR = 4.88, respectively. Multivariate analysis found age differences (p = 0.038), with OR = 1.08. The Disease Specific Survival (DSS) was worst in the PNI-positive group (log-rank p-value = 0.0011), where the probability of dying occurred in the 12-24 months period (log-rank p-value = 0.002). PNI-positive salivary gland MEC is an independent prognostic factor, with poor DSS, increased locoregional recurrence, close correlation with a more aggressive pattern of the disease, and should be reviewed as a high grade histological criteria. Our findings may imply changes in the clinical approach with a more aggressive attitude in the overall treatment.

Mucoepidermoid carcinoma: A retrospective clinicopathologic study of 25 cases

Background

Salivary gland tumors are rare and clinically represent a diverse group of neoplasms among which mucoepidermoid carcinoma (MEC) is a relatively common salivary gland tumor with varying potential for aggressive behavior. The purpose of the study was aimed at to analyze the relative frequency and correlate with age, sex, anatomical site and histological grade of MEC and compare the findings with epidemiological data from different geographic locations.

Materials and Methods

Twenty-five cases diagnosed with MEC during the period June 1985 to June 2004 (19 years) were retrieved from the Department of Pathology, Government Medical College and Hospital, Ambajogai, and clinical data were recorded and reviewed histopathologically.

Results

The relative frequency of MEC was 13.15%. Low-grade MEC (44%) was the most common, followed by intermediate-grade MEC (36%) and high-grade MEC (20%). The mean age for occurrence of MEC was 44.28 ± 13.29 years. MEC was predominant in females (60%) than males (40%). Thus, the overall female-male ratio was 1.5:1. Among minor salivary glands, palate (48%) was the most common site, and among major salivary glands, parotid gland (16%) was the common site.

Conclusion

Comparing the present data with previous studies on MEC, one may infer that some demographic characteristics and the predominance vary in different geographic regions. Analysis of the distribution and particular features of MEC in a specific population helps in establishment of appropriate treatment.

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.

Ki-67 Proliferation Rate as a Prognostic Marker in Major Salivary Gland Carcinomas

Objectives

The study was performed to evaluate the prognostic relevance of cell proliferation associated with Ki-67/Mib-1 immunostaining in malignant tumors of the major salivary glands.

Methods

Cell proliferation was evaluated by Mib-1 antibody against Ki-67 antigen in 41 patients with cancer of the parotid or submandibular glands, including 14 acinic cell carcinomas, 12 ductal carcinomas, 7 mucoepidermoid carcinomas, 5 carcinomas ex pleomorphic adenoma, 1 adenoid cystic carcinoma, 1 undifferentiated carcinoma, and 1 polymorphous low-grade adenocarcinoma.

Results

Patients with Ki-67 values of more than 15% and those with Ki-67 values of 15% or less differed both in disease-free survival (p < 0.001) and in overall survival (p < 0.001). We evaluated the association between Ki-67 and time to recurrence in correlation to age, sex, ductal histotype, and N stage; the Cox regression model was significant (p = 0.013). In the group of patients with T1 and T2 cancers, those with Ki-67 values of 15% or less had better survival rates than did those with Ki-67 values of more than 15% (p = 0.004). In the group of patients with NO cancers, those with Ki-67 values of 15% or less had a better survival than did those with Ki-67 values of more than 15% (p < 0.001).

Conclusions

To our knowledge, this is the first study to stratify different risk classes in early T1–T2 or NO malignant tumors of the major salivary glands that identified aggressive lesions with elevated Ki-67 expression at an initial stage.

Upregulation of RAD51 expression is associated with progression of thyroid carcinoma

AIMS

RAD51 participates in homologous recombination repair (HRR) of double-stranded DNA breaks (DSBs) which may cause genomic instability and cancer. The aim of this study was to investigate RAD51 gene expression at transcriptional and translational levels to measure mRNA and protein level and to correlate its relationship with proliferation marker, Ki67 in thyroid cancer patients. This study also explored correlation of these genes with different clinicopathological parameters of the study cohort by Spearman's rank correlation coefficient.

METHODS

Quantitative real time polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to detect mRNA transcript levels and protein expression of RAD51 and Ki67 in 102 cases of thyroid cancer tissues and equal number of uninvolved healthy thyroid tissue controls.

RESULTS

Data showed that expression for both RAD51 and Ki67 was significantly increased in thyroid cancer (p<0.001). High RAD51 and Ki67 expression was associated with later stages, poor tissue differentiation, large tumor size, positive lymph node metastasis and distant metastasis. The correlation analysis demonstrated a strong positive correlation (r=0.461) between RAD51 and Ki67 on mRNA level and on protein level (r=0.866). Strong correlation was observed between clinicopathological characteristics and selected molecules.

CONCLUSION

The present study concluded that upregulation of RAD51 and overexpression of Ki67 may be associated with the progression of thyroid cancer.

Clinicopathologic and Immunohistochemical Study of Intraoral Mucoepidermoid Carcinoma

OBJECTIVE: The purpose of this study is to assess the clinicopathologic and immunohistochemical features of intraoral mucoepidermoid carcinomas and its relationship with the prognosis.

STUDY DESIGN AND SETTING: From 1953 to 1993, 27 patients with intraoral mucoepidermoid carcinomas surgically treated were selected for this study. Clinical data were obtained from the medical records, the microscopic slides were reviewed, the tumors were graded, and immunohistochemical analysis for p53, PCNA, cerbB-2, and CEA were carried out.

RESULTS: The tumors were more frequent in patients between 40 and 60 years of age (40.7%), without gender predilection. Hard palate was the most common site with 13 cases (48%). T2 was the more frequent stage (48%) and 2 patients (7.4%) were staged as N + . Most tumors (48%) were classified as low grade of malignancy. The expression of PCNA was associated to high-grade tumors ( P = .00610) and c-erbB-2 to low grade tumors ( P = .03958). No recurrence was noted in most of the cases (22 cases, 81.5%). Three cases (11.1%), however, showed local recurrence and 2 patients (7.4%) died because of the disease. The analysis of the overall survival rate showed that male patients ( P = .04249), stage N ( P = .05948), high grade of malignancy ( P = .0009), strong expression of PCNA ( P = .09128), and weak expression of c-erbB-2 ( P = .03334) had the lowest survival rates.

CONCLUSION: Our results showed that patients with intraoral mucoepidermoid carcinoma had a reduced survival expectation if they were of the male gender, with regional metastasis, high grade of malignancy, strong expression of PCNA and weak expression of c-erbB-2.

Deregulation of base excision repair gene expression and enhanced proliferation in head and neck squamous cell carcinoma

Defects in the DNA damage repair pathway contribute to cancer. The major pathway for oxidative DNA damage repair is base excision repair (BER). Although BER pathway genes (OGG1, APEX1 and XRCC1) have been investigated in a number of cancers, our knowledge on the prognostic significance of these genes and their role in head and neck squamous cell carcinoma is limited. Protein levels of OGG1, APEX1 and XRCC1 and a proliferation marker, Ki-67, were examined by immunohistochemical analysis, in a cohort of 50 HNSCC patients. Significant downregulation of OGG1 (p<0.04) and XRCC1 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant upregulation of APEX1 (p<0.05) and Ki-67 (p<0.05) was observed in poorly differentiated HNSCC compared to mod-well-differentiated cases. Significant correlation was observed between XRCC1 and OGG1 (r=0.33, p<0.02). Inverse correlations were observed between OGG1 and Ki-67 (r=-0.377, p<0.005), between APEX1 and XRCC1 (r=-0.435, p<0.002) and between OGG1 and APEX1 (r=-0.34, p<0.02) in HNSCC. To confirm our observations, we examined BER pathway genes and a proliferation marker, Ki-67, expression at the mRNA level on 50 head and neck squamous cell carcinoma (HNSCC) and 50 normal control samples by quantitative real-time polymerase chain reaction. Significant downregulation was observed in case of OGG1 (p<0.04) and XRCC1 (p<0.02), while significant upregulation was observed in case of APEX1 (p<0.01) and Ki-67 (p<0.03) in HNSCC tissue samples compared to controls. Our data suggested that deregulation of base excision repair pathway genes, such as OGG1, APEX1 and XRCC1, combined with overexpression of Ki-67, a marker for excessive proliferation, may contribute to progression of HNSCC in Pakistani population.

Prognostic value of O-6-methylguanine-DNA methyltransferase loss in salivary gland carcinomas

BACKGROUND

The purpose of this study was to determine the prognostic value of O-6-methylguanine-DNA methyltransferase (MGMT) inactivation in a group of 286 patients with salivary gland carcinoma and matched histologically normal tissues.

METHODS

MGMT promoter methylation was studied in 36 patients with salivary gland carcinoma and 19 histologically matched normal tissues by pyrosequencing. MGMT protein expression was examined in 286 patients with salivary gland carcinomas and histologically matched normal tissues by immunohistochemistry on tissue microarrays. The results were correlated to demographic, clinicopathologic parameters, and disease follow-up data.

RESULTS

MGMT hypermethylation was significantly (p = .021) associated with the protein loss. MGMT loss was found in 39.2% of salivary gland carcinomas and was predominant in aggressive tumors (poorly differentiated, grade III, regional lymph node involved). MGMT loss significantly (p = .004) predicted poor clinical outcome of salivary gland carcinomas and defined high-risk subgroups in clinically favorable tumor groups.

CONCLUSION

We suggest that immunohistochemical evaluation of nuclear MGMT protein might serve as a tool for the prediction of overall survival in patients with salivary gland carcinoma.

High-grade mucoepidermoid carcinoma of the columella successfully reconstructed using bilateral nasolabial flaps set up in a sandwich shape and an auricular cartilage graft after surgical resection

Mucoepidermoid carcinoma (MEC) usually originates from the salivary glands. However, there has been no report on mucoepidermoid carcinoma of the columella. In this study, we report the case of a high-grade MEC of the columella that was successfully reconstructed after surgical resection with bilateral nasolabial flaps set up in a sandwich shape and an auricular cartilage graft. A 66-year-old man presented with a nodule on the columella. Histological findings were suggestive of a high-grade mucoepidermoid carcinoma. Wide excision was performed, and the defects of the columella and the nasal floor were reconstructed with bilateral nasolabial flaps set up in a sandwich shape and an auricular cartilage graft. The postoperative cosmetic result was good with excellent tissue texture. The reconstructed columella had an appropriate, not bulky, width as well as satisfactory height and depth. This reconstructive technique is particularly useful for correcting the large defect of the columella with nasal septum and/or nasal floor defects.

Takahashi R, Nagai T, Yoshida M, Suzuki F, Obikane H, Yamashina M, Matsubayashi J. Immunohistochemical analysis of salivary gland tumors: application for surgical pathology practice

Salivary gland tumors are relatively uncommon and there exists a considerable diagnostic difficulty owing to their diverse histological features in individual lesions and the presence of a number of types and variants, in addition to overlapping histological patterns similar to those observed in different tumor entities. The classification is complex, but is closely relevant to the prognostic and therapeutic aspects. Although hematoxylin-eosin staining is still the gold standard method used for the diagnosis, immunohistochemistry (IHC) can enhance the accuracy and be a helpful tool when in cases to investigate the subjects that cannot be assessed by histological examination, such as the cell nature and differentiation status, cell proliferation, and tumor protein expression. This review depicts on the practical diagnostic utility of IHC in salivary gland tumor pathology under the following issues: assessment of cell differentiation, focusing on neoplastic myoepithelial cells; discrimination of histologically mimic tumor groups; diagnosis of specific tumor types, e.g., pleomorphic adenoma, adenoid cystic carcinoma, and salivary duct carcinoma; and evaluation of malignancy and prognostic factors. IHC plays a limited, even though important, role in the diagnosis of salivary gland tumors, but is often useful to support the histological assessment. However, unfortunately few tumor type-specific markers are still currently available. For these reasons, IHC should be considered a method that can be used to assist the final diagnosis, and its results themselves do not directly indicate a definitive diagnosis.

The prognostic significance of p63 and Ki-67 expression in myoepithelial carcinoma

Background

Myoepithelial carcinoma is a rare tumour. The clinical and biological behaviours of these tumours are variable. Although many factors have been evaluated as potential prognostic indicators, including clinical stage, site and size of the tumour, high proliferative activity, extensive invasion into the surrounding tissue, perineural permeation, the abnormal presence of nuclear DNA content, and marked cellular pleomorphism, there are no definite histological features that clearly correlate with their behaviour. Thus, conclusions regarding prognostic factors and ideal treatment may emerge as the number of investigated myoepithelial carcinoma cases accumulate.

Methods

Using immunohistochemistry, expression levels of p63 and Ki-67 were determined in 16 myoepithelial carcinoma samples and correlated with clinicopathological characteristics and patient prognosis.

Results

p63 expression was detected in six of the myoepithelial carcinoma tissues (37.5%) and Ki-67 was detected in five (31.3%). In addition, p63 and Ki-67 expression levels were associated with myoepithelial carcinoma recurrence and metastasis. All six patients with p63-positive expression died due to disease or cardiovascular disease (mean survival time = 50.5 months), and p63 expression was statistically significant with respect to survival (P = 0.01). Four patients with Ki-67-positive expression died due to disease or cardiovascular disease (mean survival time = 44.0 months); however, there was no statistically significant difference between Ki-67 expression and survival (P = 0.24).

Conclusions

Recurrence and metastasis in myoepithelial carcinomas are more frequent in p63-positive and Ki-67-positive EMCs, and poor prognosis is associated with overexpression of p63.

A reappraisal of the MECT1/MAML2 translocation in salivary mucoepidermoid carcinomas

The MECT1/MAML2 translocation is identified in a large proportion of mucoepidermoid carcinomas (MEC) of the salivary gland and is an emerging favorable prognosticator. However, there are conflicting data on this translocation's specificity, restriction to low/intermediate MEC, and strength as a prognosticator. We present our experience with the MECT1/MAML2 translocation in a large cohort of MECs to address these issues. We analyzed 55 salivary MEC and 36 potential MEC mimics (24 Warthin tumors, 5 oncocytomas, 3 squamous cell carcinomas, 2 squamoid salivary duct carcinomas, 1 lymphoepithelial cyst, 1 Schneiderian carcinoma ex papilloma) for presence of the MECT1/MAML2 translocation by fluorescent in-situ hybridization (FISH) and real-time RT-PCR. Overall, MECT1/MAML2 translocation was present in 36/55 (66%) of MEC whereas all 36 non-MEC were negative for translocation. Low or intermediate-grade MEC had a higher frequency of translocation (75%) than high-grade MEC (46%) (P=0.039). Translocation positive cases had a better disease-specific survival (log rank P=0.026) although 2 patients still died of disease. Within high-grade MEC, MECT1/MAML2 positive tumors had lower rates of anaplasia (P=0.001), and mitotic counts (P=0.012). Thus, MECT1/MAML2 translocation is highly specific for MEC and imparts a better prognosis. However, it is frequent even within high-grade MEC and can be seen in lethal cases suggesting that translocation status should not supersede conventional parameters. There are 2 distinct subgroups within high-grade MEC, and the translocation negative tumors may actually be more appropriately categorized as another tumor type (such as adenosquamous carcinoma).

Overexpression of EGFR and absence of C-KIT expression correlate with poor prognosis in salivary gland carcinomas

AIMS

To evaluate the prognostic impact of expression of receptor tyrosine kinases epidermal growth factor receptor (EGFR), HER2, and C-KIT in relation to established clinicopathological parameters in salivary gland carcinomas.

METHODS AND RESULTS

Immunohistochemistry for EGFR, HER2, C-KIT and the proliferation marker Ki67 was performed in 101 cases of salivary gland carcinoma and related to long-term clinical follow-up. Immunopositivity of C-KIT was common in adenoid cystic carcinoma (92%). Lack of C-KIT expression occurred in salivary duct carcinoma (P < 0.001) and was associated with high-grade tumours (P = 0.002), positive lymph nodes (P = 0.002) and high expression of Ki67 (P = 0.001). HER2 was typically expressed in salivary duct carcinomas (83%), but was not associated with any other parameter. EGFR overexpression occurred independently of histological type and clinical parameters. On univariate survival analysis, overexpression of EGFR (P = 0.011) and lack of C-KIT (P = 0.014) were associated with worse prognosis, whereas HER2 was of no prognostic significance. On multivariate analysis, the strongest negative predictor of survival was high proliferative activity measured by Ki67 (P = 0.002), followed by presence of residual tumour (P = 0.006), overexpression of EGFR (P = 0.026) and advanced tumour stage (P = 0.041).

CONCLUSIONS

The expression of receptor tyrosine kinases confers additional prognostic impact on disease-specific survival. EGFR overexpression is an independent negative prognostic factor.

Salivary gland cancers: current treatments, molecular characteristics and new therapies

Salivary gland cancers are relatively rare and quite diverse. Current therapy relies on local ablation. There are few large clinical trials or randomized trials to guide treatment, especially for metastatic disease. This article reviews the epidemiology, staging, molecular characteristics, and treatment evidence for the most common types of salivary cancers and suggests potential future diagnostic and treatment directions. Progress in understanding the molecular and cell biology of salivary gland cancers may lead to the development of targeted therapies in these rare tumors. Multidisciplinary and multi-institutional collaborative studies are needed to help improve survival in salivary gland cancers.

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.

MECT1-MAML2 fusion transcript defines a favorable subset of mucoepidermoid carcinoma

PURPOSE

Mucoepidermoid carcinoma is the most common primary malignancy of the salivary gland. Mucoepidermoid carcinoma translocated gene 1-mastermind-like gene family (MECT1-MAML2) gene fusion was identified from a recurring t(11;19)(q21;p13) translocation, which is often the sole cytogenetic alteration in this disease. This fusion transcript has been frequently detected in mucoepidermoid carcinoma and shown to be involved in the transformation of epithelial cells. However, its clinicopathologic significance remains unclear.

EXPERIMENTAL DESIGN

Seventy-one cases of mucoepidermoid carcinoma and 51 cases of nonmucoepidermoid carcinoma salivary gland tumors (including 26 Warthin tumor cases) were retrospectively analyzed. RNA was extracted from archival materials: histologic paraffin specimens in all cases and cytologic specimens in 10 mucoepidermoid carcinoma cases. The MECT1-MAML2 fusion transcript was detected by a reverse transcription-PCR assay, which can be applied to both histologic and cytologic specimens. The presence of the fusion transcript was correlated with relevant clinicopathologic and survival data of the mucoepidermoid carcinoma patients.

RESULTS

The MECT1-MAML2 fusion transcript was detected in 27 of the 71 (38%) mucoepidermoid carcinoma cases but not in any case of nonmucoepidermoid carcinoma tumors. The reverse transcription-PCR results showed no difference between histologic and cytologic specimens. Detection of the MECT1-MAML2 fusion transcript was associated with a less advanced clinical stage and a low-grade tumor histology. The presence of the transcript was associated with longer disease-free and overall survivals on univariate analysis and emerged as an independent prognostic factor for longer overall survival on multivariate analysis.

CONCLUSIONS

The MECT1-MAML2 fusion transcript may be specific to mucoepidermoid carcinoma and associated with a distinct mucoepidermoid carcinoma subset that exhibits favorable clinicopathologic features and an indolent clinical course.

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.

Sclerosing mucoepidermoid carcinoma of the salivary glands

Mucoepidermoid carcinoma (MEC) comprises approximately 30% of all salivary gland malignancies, making it the most common malignant tumor of the salivary glands. Multiple histologic variants with a wide range of differentiation have been described. Sclerosing MEC (SMEC) is a rare subtype that may be misdiagnosed as a benign reactive condition or low-grade non-SMEC malignancy. We report 4 cases of SMEC and evaluated them with Her-2/neu and MIB-1 to determine whether an association exists between the histologic grade and immunohistochemical findings. In 3 cases, histologic examination demonstrated relatively well-circumscribed, nonencapsulated tumors composed of extensive central sclerosis with keloid-like stroma and scattered epithelial islands of low-grade MEC. In the fourth case, the tumor showed similar sclerotic stroma; but the epithelial component was of intermediate grade. In all 4 cases, eosinophils and neutrophils were part of the inflammatory infiltrate; and the edges were surrounded by lymphoid tissue, with germinal center formation and residual epithelial islands. A Mayer mucicarmine stain revealed abundant intracytoplasmic mucin. We found MIB-1 labeling indices of 5% or less in cases 1, 2, and 3 and 12% in case 4, suggesting an association between MIB-1 index and tumor grade. The tumors were negative for Her-2/neu in all 4 cases. The latter seems to bear no relationship to tumor grade.

Id3 is a novel regulator of p27kip1 mRNA in early G1 phase and is required for cell-cycle progression

P27kip is a key inhibitory protein of the cell-cycle progression, which is rapidly downregulated in early G1 phase by a post-translational mechanism involving the proteosomal degradation. In this study, using a wounding model that induces cell-cycle entry of human dermal fibroblasts, we demonstrate that p27mRNA is downregulated when cells progress into the G1 phase, and then it returns to its basal level when cells approach the S phase. By using a quantitative polymerase chain reaction screening we identified inhibitors of differentiation (Id3), a bHLH transcriptional repressor, as a candidate mediator accounting for p27 mRNA decrease. Id3 silencing, using an small interfering RNA approach, reversed the injury mediated p27 downregulation demonstrating that Id3 is involved in the transcriptional repression of p27. Reporter gene experiments and a chromatin immunoprecipitation assay showed that Id3 likely exerts its repressive action through ELK1 inhibition. By inhibiting early p27 downregulation, Id3 depletion blocked (i) the G1-phase progression as assessed by the inhibition of pRb phosphorylation and p130 degradation and (ii) the G1/S transition as observed by the inhibition of cyclin A induction, demonstrating that p27 mRNA decrease is required for cell proliferation. Apart from its effect on the early p27 diminution, Id3 appears also involved in the control of the steady-state level of p27 at the G1/S boundary. In conclusion, this study identifies a novel mechanism of p27 regulation which besides p27 protein degradation also implicates a transcriptional mechanism mediated by Id3.

Expression of p21WAF in salivary gland mucoepidermoid carcinoma and its relation to histologic grade

The biologic behavior and factors influencing the development of salivary gland mucoepidermoid carcinoma are not fully understood. Alteration of the cyclin-dependant kinase inhibitor p21(WAF) could cause uncontrolled proliferation leading to cancer. Thirty-five mucoepidermoid carcinomas were graded and immunohistochemically stained for p21(WAF). The percentage of positive tumor cells was determined using an eyepiece graticule and a computer-assisted image analyzer, which revealed 8.6% and 22.9% of the cases to be positive for p21(WAF), respectively. A statistically significant correlation was not observed between p21(WAF) and grading. Considering the absence of p21(WAF) expression in most mucoepidermoid carcinomas, it appears that the inhibitory effect of p21(WAF) on cell growth is removed in most cases. Given the lack of correlation with tumor grade, it is possible that the impact of p21(WAF) is in the earlier stages of tumorigenesis. A p53-independent pathway of p21(WAF) induction may exist for the small proportion of tumors that showed positivity.

Salivary mucoepidermoid carcinoma: revisited

Mucoepidermoid carcinoma (MEC) is a malignant epithelial neoplasm composed of varying proportions of mucous, epidermoid, intermediate, columnar, and clear cells and often demonstrates prominent cystic growth. MEC is usually subclassified as low, intermediate, or high grade on the basis of its histologic features, including the presence of cystic spaces, cellular differentiation, proportion of mucous cells, growth pattern, type of invasion, and cytologic atypia. Because even low-grade neoplasms may metastasize, the term mucoepidermoid tumor is inappropriate. The 3-level grading approach to tumor classification has found general acceptance among pathologists; differences in biologic behavior can be demonstrated even though clinical stage has become a better prognosticator. However, in the case of MEC, no universal agreement exists regarding which histologic grading criteria are most the useful, and grading has varied. These issues have led to the investigation of more subjective systems. We describe these new schemes, the histologic variants of MEC, and the ancillary methods that allow for further stratification of patients with MEC, especially for patients with grade 2 tumors, which have a variable and unpredictable clinical course.

Cytokeratin profile in mucoepidermoid carcinoma is not related to its histological grading of malignancy

The objective of this experiment was to determine the relationship between the expression of cytokeratins (CKs) and histologic grading in MEC. Eleven cases of MEC were selected and graded as low, intermediate and high-grade tumors. The expression of CKs 7, 8, 10, 13 and 14 was assessed immunohistochemically using streptavidin-biotin complex method. The results showed that the studied CKs were expressed in most cases of MEC, independently of histologic grading. Nonetheless, low-grade tumors demonstrated intense staining of CK 7 and 8; additionally, CK 10 and 13 were more pronounced in this grade. The immunoexpression was variable according to cellular type and organization pattern of the tumor. Mucous cells were positive for CK 7 and 8; epidermoid cells were stained for CK 10, 13 and 14; CK 7, 8, 10 and 14 were observed in intermediate cells, and CK 7 was occasionally seen in clear cells. Cystic structures and duct-like elements in MEC were positive for CK 7 and 8, whereas solid nests showed positivity for all CKs. These results suggest that expression profile of these proteins does not reflect the biological behavior of MCE, however, it guides the detection of cellular types and differential diagnosis from other salivary gland tumors.

Mucoepidermoid carcinoma of minor salivary glands: a clinical study of 16 cases and review of the literature

OBJECTIVE

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of salivary glands with a widely diverse biologic behavior that is correlated with the histological grade of the tumor. The purpose of this study was to evaluate the clinical outcomes of MEC of minor salivary glands in a group of 16 patients, who were treated in our clinic, and to discuss the management of this carcinoma.

MATERIALS AND METHODS

Between 1985 and 2000, 16 patients with MEC of minor salivary glands were treated in the Clinic of Oral and Maxillofacial Surgery of the 'G. Papanikolaou' General Hospital, in Thessaloniki. The age range was 16-65 years. The distribution of the primary sites was: hard plate (one), soft palate (two), hard and soft palate (three), hard and soft palate with spread in paranasal sinus and nasal cavity (one), buccal mucosa (three), hard palate, alveolar process and buccal mucosa (two), and retromolar triangle (our). The tumors were clinically staged according to the tumor nodes metastase (TNM) system (Seifert, 1991). All patients were treated radically with surgery. The surgery was combined with radiotherapy in nine patients. Radiotherapy was delivered using Co-60. Doses ranged from 50 to 60 Gy and the duration of the therapy ranged from 25 to 35 days. Immunohistochemical assay of the expression of the Ki-67 antigen was performed on a subset of 15 cases.

RESULTS

The mean follow-up range was 4-14 years. From the 16 patients with MECs 10 (62.5%) were alive and five (35.6%) had died from the disease. Four patients were free of the disease for more than 5 years (range 8-14), five patients were free of the disease for 5 years and one patient was free of the disease for 4 years. One patient lived more than 10 years and died from another cause. Local recurrence developed in one patient 10 years after the initial treatment. Lymph node metastases occurred in one patient within the first year after the initial surgical treatment. Distant metastases (two in bones and one in lungs) occurred in three patients within 2 years after completing the treatment. The Pearson chi-square statistical analysis was used for comparing the Ki-67 values in correlation with histological grade of the tumors. The Ki-67 expression was only 1% in low-grade MECs, while in intermediate-grade tumors it was estimated between 3 and 4%. The high-grade tumors had increased expression (10%) of tumor cells.

CONCLUSION

Complete surgical excision is the treatment of choice for MECs. Adequate excision is important in all grades of tumors. Prognosis of MECs is a function of the histological grade, adequacy of excision and clinical staging. The immunohistochemical study of Ki-67 expression may provide additional prognostic information for this tumor.

Prognostic relevance of cell proliferation in head and neck tumors

Cell proliferative activity has been extensively investigated in head and neck tumors. Ki67/MIB-1 immunostaining, tritiated thymidine or bromodeoxyuridine labeling indices, DNA S-phase fraction, proliferating cell nuclear antigen expression, potential doubling time and analysis of the nucleolar organizer region associated proteins (AgNORs) have shown significant correlation with prognosis in 4806 cases of tumors of the oral cavity, salivary glands, pharynx and larynx. However, this was not observed in 2968 other reported cases. Discrepancies may depend on various factors: the heterogeneity of the series, which include tumors from various anatomic sites and patients treated with different therapy, and the lack of standardization of methods for assessing cell proliferation. Furthermore, none of the methods currently applied can by themselves define the actual proliferative activity, as it depends both on the proportion of cells committed to the cycle (growth fraction) and the speed of the cell cycle. Indeed, the actual proliferative activity of a tumor could well be measured by the equation [PA = Ki67 or MIB-1 scores x AgNORs], as we did in pharyngeal carcinoma. Provided that large and homogeneous series are evaluated by standardized methods, cell proliferative activity can still be regarded as an inexpensive and reliable prognostic factor in head and neck tumors.

Mel-CAM (CD146) expression in parotid mucoepidermoid carcinoma

Mel-CAM (CD146) is a cell-cell adhesion protein found in normal and tumoral tissues. The aim of this study was to analyse Mel-CAM expression in mucoepidermoid carcinoma (MEC), and assess its importance in prognosis and its utility in differentiating high-grade MEC from squamous cell carcinoma (SCC). Immunohistochemical expression of Mel-CAM in 41 parotid MEC was correlated with clinical parameters. Ten cases of oral cavity SCC were included for comparison. Mel-CAM expression was found in 92.7% of the MEC but was not expressed by the SCC. Mel-CAM expression was greater in intermediate/high grade tumors, was weaker in patients that presented local recurrence, regional and distant metastasis, but no correlation between Mel-CAM and clinical stage and survival of the patients was found. Decreased Mel-CAM expression can impair cellular contact properties, facilitating growth, cell spreading and metastasis in MEC. Mel-CAM can also be useful in differentiating high grade MEC from SCC.