Prognostic significance of cell proliferation in mucoepidermoid carcinomas of the salivary gland: clinicopathological study using MIB 1 antibody in paraffin sections

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.

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.

Nuclear Multidrug Resistance-Related Protein 1 Is Highly Associated with Better Prognosis of Human Mucoepidermoid Carcinoma through the Suppression of Cell Proliferation, Migration and Invasion

Objectives

Multidrug resistance-related protein 1 (MRP1) overexpression is a well acknowledged predictor of poor response to chemotherapy, but MRP1 also correlated to better prognosis in some reports, especially for patients not pretreated with chemotherapy. In our previous study, we found nuclear translocation of MRP1 in mucoepidermoid carcinoma (MEC) for the first time. The purpose of this study was to further investigate the function of nuclear MRP1 in MEC.

Materials and Methods

Human MEC tissue samples of 125 patients were selected and stained using immunohistochemistry. The expression level of total MRP1/nuclear MRP1 of each sample was evaluated by expression index (EI) which was scored using both qualitative and quantitative analysis. The correlations between the clinicopathologic parameters and the EI of nuclear MRP1 were analyzed using Spearman’s rank correlation analysis, respectively. The effects of RNAi-mediated downregulation of nuclear MRP1 on MEC cells were assessed using flow cytometric analysis, MTT assay, plate colony formation assay, transwell invasion assay and monolayer wound healing assay.

Results

In this study, we found the EI of nuclear MRP1 was negatively correlated to the pathologic grading (r = -0.498, P<0.01) / clinical staging (r = -0.41, P<0.01) / tumor stage (r = -0.28, P = 0.02) / nodal stage (r = -0.29, P<0.01) of MEC patients. The RNAi-mediated downregulation of nuclear MRP1 further proved that the downregulation of nuclear MRP1 could increase the cell replication, growth speed, colony formation efficiency, migration and invasion ability of MEC cells.

Conclusion

Our results suggested that nuclear MRP1 is highly associated with better prognosis of human mucoepidermoid carcinoma and further study of its function mechanism would provide clues in developing new treatment modalities of MEC.

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.

Salivary mucoepidermoid carcinoma revisited

Clinicopathological features, prognosis and therapeutic strategies for mucoepidermoid carcinoma originating in salivary and salivary-type glands of the head and neck are reviewed. We emphasise histopathological aspects, appraise the value of histochemistry, electron microscopy, immunohistochemistry and cytophotometry, and discuss histogenesis and characteristic gene translocations. We additionally consider possible diagnostic difficulties, problems related to histological grading and accuracy of existing literature, and areas of controversy or uncertainty which may benefit from further investigations.

LINE-1 and Alu hypomethylation in mucoepidermoid carcinoma

BACKGROUND

Mucoepidermoid carcinoma (MEC) can be classified into low-, intermediate-, and high-grade tumors based on its histological features. MEC is mainly composed of three cell types (squamous or epidermoid, mucous and intermediate cells), which correlates with the histological grade and reflects its clinical behavior. Most cancers exhibit reduced methylation of repetitive sequences such as Long INterspersed Element-1 (LINE-1) and Alu elements. However, to date very little information is available on the LINE-1 and Alu methylation status in MEC. The aim of this study was to investigate LINE-1 and Alu element methylation in MEC and compare if key differences in the methylation status exist between the three different cell types, and adjacent normal salivary gland cells, to see if this may reflect the histological grade.

METHODS

LINE-1 and Alu element methylation of 24 MEC, and 14 normal salivary gland tissues were compared using Combine Bisulfite Restriction Analysis (COBRA). Furthermore, the three different cell types from MEC samples were isolated for enrichment by laser capture microdissection (LCM), essentially to see if COBRA was likely to increase the predictive value of LINE-1 and Alu element methylation.

RESULTS

LINE-1 and Alu element methylation levels were significantly different (p<0.001) between the cell types, and showed a stepwise decrease from the adjacent normal salivary gland to the intermediate, mucous and squamous cells. The reduced methylation levels of LINE-1 were correlated with a poorer histological grade. In addition, MEC tissue showed a significantly lower level of LINE-1 and Alu element methylation overall compared to normal salivary gland tissue (p<0.001).

CONCLUSIONS

Our findings suggest that LINE-1 methylation differed among histological grade mucoepidermoid carcinoma. Hence, this epigenetic event may hold value for MEC diagnosis and prognostic prediction.

Genomic profiles and CRTC1-MAML2 fusion distinguish different subtypes of mucoepidermoid carcinoma

Mucoepidermoid carcinoma is the most common salivary gland malignancy, and includes a spectrum of lesions ranging from non-aggressive low-grade tumors to aggressive high-grade tumors. To further characterize this heterogeneous group of tumors we have performed a comprehensive analysis of copy number alterations and CRTC1-MAML2 fusion status in a series of 28 mucoepidermoid carcinomas. The CRTC1-MAML2 fusion was detected by RT-PCR or fluorescence in situ hybridization in 18 of 28 mucoepidermoid carcinomas (64%). All 15 low-grade tumors were fusion-positive whereas only 3 of 13 high-grade tumors were fusion-positive. High-resolution array-based comparative genomic hybridization revealed that fusion-positive tumors had significantly fewer copy number alterations/tumor compared with fusion-negative tumors (1.5 vs 9.5; P=0.002). Twelve of 18 fusion-positive tumors had normal genomic profiles whereas only 1 out of 10 fusion-negative tumors lacked copy number alterations. The profiles of fusion-positive and fusion-negative tumors were very similar to those of low- and high-grade tumors. Thus, low-grade mucoepidermoid carcinomas had significantly fewer copy number alterations/tumor compared with high-grade mucoepidermoid carcinomas (0.7 vs 8.6; P<0.0001). The most frequent copy number alterations detected were losses of 18q12.2-qter (including the tumor suppressor genes DCC, SMAD4, and GALR1), 9p21.3 (including the tumor suppressor genes CDKN2A/B), 6q22.1-q23.1, and 8pter-p12.1, and gains of 8q24.3 (including the oncogene MAFA), 11q12.3-q13.2, 3q26.1-q28, 19p13.2-p13.11, and 8q11.1-q12.2 (including the oncogenes LYN, MOS, and PLAG1). On the basis of these results we propose that mucoepidermoid carcinoma may be subdivided in (i) low-grade, fusion-positive mucoepidermoid carcinomas with no or few genomic imbalances and favorable prognosis, (ii) high-grade, fusion-positive mucoepidermoid carcinomas with multiple genomic imbalances and unfavorable prognosis, and (iii) a heterogeneous group of high-grade, fusion-negative adenocarcinomas with multiple genomic imbalances and unfavorable outcome. Taken together, our studies indicate that molecular genetic analysis can be a useful adjunct to histologic scoring of mucoepidermoid carcinoma and may lead to development of new clinical guidelines for management of these patients.

Prognostic significance of Ki-67 in salivary gland carcinomas

BACKGROUND

Salivary gland carcinomas are a heterogeneous group of tumors with varying malignant potential. In this study, we evaluated the proliferative marker Ki-67 in salivary gland carcinomas and related the Ki-67 index to clinical data.

METHODS

A total of 176 salivary gland carcinomas of 13 different subtypes were stained immunohistochemically for Ki-67. The number of Ki-67 positive cells was counted and the Ki-67 index was calculated as the percentage of positive tumor cells.

RESULTS

The Ki-67 median value was 26 (range 1-99). The median follow-up time was 6.9 years (range 0-19 years). The 5- and 10-year crude survival was 70% and 59%, respectively. In univariate analysis, Ki-67 index, stage, vascular invasion and tumor grade were significantly related to crude survival, but in multivariate analysis only Ki-67 index, age, and stage were independent prognostic factors.

CONCLUSION

We showed that irrespective of subtyping, grading or morphological appearance of tumor, the Ki-67 index is an important and independent prognosticator. Clinical and histo-pathological data must be considered, when planning the treatment of the individual patient. We have shown that besides stage and age of the patient, Ki-67 is a strong, independent prognostic factor.

Histologic grading and prognostic biomarkers in salivary gland carcinomas

Both the variety and rarity of salivary gland carcinomas pose challenge for using histologic grade and biomarkers to predict outcome. Mucoepidermoid carcinoma is the histologic subtype for which grading is most prognostically and therapeutically relevant. This tumor is graded using standard schemes in a 3-tier manner with the intermediate-grade category shows the most variability between grading systems and thus the most controversy in management. The t(11;19)(q21; p13) MECT1-MAML2 translocation may be an objective marker that can help to further stratify difficult cases. Adenoid cystic carcinomas are graded based on pattern with solid areas correlating with a worse prognosis. Occasionally, adenoid cystic carcinomas may undergo transformation to highly aggressive pleomorphic high-grade carcinomas with frequent nodal metastases. Comparative genomic hybridization has revealed several chromosomal regions (such as 1p32-p36, 6q23-q27) of prognostic interest in adenoid cystic carcinoma. Carcinoma ex-pleomorphic adenoma is actually a category of tumors rather than a single tumor type with both aggressive and indolent versions. These tumors should be further qualified as to type/grade of carcinoma and extent, as intracapsular and minimally invasive tumors behave favorably. Acinic cell carcinomas, although generally considered low grade, can recur, metastasize, or even prove lethal in a significant number of cases suggesting amenability to a grading scheme to separate these biologic groups. Although aggressive histologic parameters (anaplasia, necrosis, and mitoses) are predictive of poor outcome, a standard grading scheme does not yet exists. Acinic cell carcinomas can also undergo high-grade transformation.

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).

Reduction of 15-hydroxyprostaglandin dehydrogenase expression is an independent predictor of poor survival associated with enhanced cell proliferation in gastric adenocarcinoma

Prostaglandin (PG) E(2) promotes gastrointestinal carcinogenesis and tumor progression. We determined the correlations between pattern of expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a catabolic enzyme for biological inactivation of PGE(2), in gastric adenocarcinoma and various clinicopathological factors and patient outcome in an attempt to elucidate its biological significance. In 35 of 71 cases of gastric adenocarcinoma, expression of 15-PGDH protein was reduced in tumor tissues. Multivariate analysis revealed reduction of 15-PGDH expression to be an independent predictor of poor survival. The proportion of Ki67-positive cells in 15-PGDH-negative adenocarcinoma was higher than that in 15-PGDH-positive adenocarcinoma. No differences were found in clinicopathological parameters between patients with cyclooxygenase-2 (COX-2)-positive tumors and those with COX-2 negative tumors. In an in vitro study, use of specific siRNA to silence 15-PGDH or a specific inhibitor of 15-PGDH enhanced cell proliferation in the gastric cancer cell line AGS, which expresses 15-PGDH. These findings suggest that reduction of 15-PGDH is an independent predictor of poor survival associated with enhancement of cell proliferation in gastric adenocarcinoma.

Sialoblastoma: utility of Ki-67 and p53 as a prognostic tool and review of literature

Sialoblastoma is a rare tumor of the salivary gland that commonly occurs in the parotid gland and occasionally in the sub-mandibular gland. The malignant potential of sialoblastoma has been documented in only 3 of 32 cases of sialoblastoma reported thus far. In the last 15 years, we have encountered 2 cases of sialoblastoma, in a newborn and in a 15-year-old boy, both arising within the parotid gland. Case 1 has been previously reported and although there were 2 recurrences, at 1 and 9 years post resection, it has shown benign biological behavior. Case 2 is unusual since the patient presented with metastases. We reviewed the 2 cases, including the 2 recurrences from the first case, for histologic and immunohistochemical differences. Although both cases showed similar cytomorphologic features, there was a significant difference in Ki-67 expression: 20% in case 1 (original tumor), <2% in case 1 (recurrent tumor), and nearly 70-80% in the recent malignant case. The difference is remarkable when combined with p53 expression, which was focally positive in the first case but diffusely positive in the second. This report highlights the potential utility of proliferation markers such as Ki-67 in concert with p53 expression to better predict the biological behavior of a rare but locally aggressive neoplasm.

Prognostic significance of Ki-67 and p53 as tumor markers in salivary gland malignancies in Finland: an evaluation of 212 cases

The proliferative capacity of a tumor as measured by Ki-67 nuclear antigen is one of the most powerful indicators of tumor behavior. Ki-67 is considered a useful tool in determining the aggressiveness of malignant neoplasms. p53 tumor suppressor gene mutations have been linked with the development and progression of a number of various cancer types. p53 tumor suppressor protein and the volume corrected index of Ki-67 corresponding to Ki-67 /mm2 of tumor tissue (VCI Ki-67) in salivary gland tumors were evaluated by immunohistochemistry from paraffin embedded sections in a series of 212 patients. The follow-up time in this nationwide full population-based study was up to five years. The association of clinicopathological features and the results of present study with survival were examined. In multivariate analysis high VCI Ki-67 was associated with worse survival of SGC patients (p = 0.0114). Supplementary information was brought by age (p = 0.0002), lymph node status (p = 0.0014), gender (p = 0.0017) and stage (p = 0.0191). p53 expression did not have additional value in prediction of survival (p = 0.1433) compared to the commonly clinical used parameters. In this material consisting of various salivary gland carcinomas VCI Ki-67 was a good prognostic factor for survival.

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.

Management and outcome of patients with mucoepidermoid carcinoma of major salivary gland origin: a single institution's 30-year experience

BACKGROUND

Mucoepidermoid carcinoma (MEC) is one of the most frequent epithelial malignancies of the salivary glands. Prediction of clinical outcome of MEC is challenging.

MATERIAL AND METHODS

We retrospectively reviewed 52 cases of MEC of major salivary gland origin diagnosed at the Department of Otolaryngology-Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland, during a 30-year period of 1976 to 2005. Criteria used for diagnosis were those of World Health Organization classifications valid at each time point, and criteria for grading were those recommended by Armed Forces Institute of Pathology fascicle (1996). Since 1993, the degree of cell proliferation was used at our institution as an adjunct tool when grading MEC. The majority of cases occurred in the parotid gland (n = 47, 90%) followed by the submandibular gland (n = 5, 10%).

RESULTS

We had 39% high-grade (HG), 14% intermediate-grade (IMG), and 44% low-grade (LG) MECs. T categories were T1, n = 18; T2, n = 16; T3, n = 9; T4, n = 9. Forty-nine (94%) patients were treated with curative intent. These patients underwent surgery, and 24 (49%) patients received postoperative radiotherapy. Follow-up time varied from 6 months to 9 years. Forty-five percent of HG-MEC patients and 67% of IMG-MEC patients developed locoregional failures or distant metastases during a 3-year follow-up as opposed to none of the LG-MEC patients. Of MEC patients with N0 neck, two HG-MEC patients and one IMG-MEC (8%) patient developed regional recurrence during follow-up.

CONCLUSIONS

Patient outcome in the different grades of MEC suggests a need for overview of the treatment protocol, especially with regard to LG-MEC and IMG-MEC. The apparently unusual occurrence of locoregional failures and metastases in LG-MEC suggests a restrictive approach in surgical management. However, the frequent occurrence of such failures in IMG-MEC warrants an aggressive approach with these tumors.

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.

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.

Insights into a complex group of neoplastic disease: advances in histopathologic classification and molecular pathology of salivary gland cancer

Cancers of major and minor salivary glands represent a histopathologic challenge in two major respects. The first challenge is the complexity of morphologic features and overlapping of histologic patterns in the different tumor entities many of which are relatively rare. The number of separate tumor entities to be considered in differential diagnosis has greatly increased in the two latest WHO classification systems 12 (Table I). The second challenge is prognostication based on histopathology. The clinical experience is that behavior of some salivary gland carcinomas does not correlate well with their histopathologic classification, and that tumors classified within the same category may exhibit quite different clinical outcomes. However, recent advances in histopathological classification have been combined with new tools in immunohistochemical diagnosis and prognostication including cell-proliferation markers, myoepithelial antigens, matrix metalloproteinases, steroid receptors, growth factors and their receptors. These have improved our possibilities for more specific choices in the treatment of a variety of salivary gland carcinomas. This paper will give an overview on recent developments in histopathological classification, prognostication, and molecular pathology of salivary gland cancer.

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.

P27, SKP2, and extra-cellular signal-related kinase signalling in human salivary gland mucoepidermoid carcinoma

Extra-cellular signal-related kinase (ERK) can modulate P27 in several ways. ERK is phosphorylated in a subset of salivary gland mucoepidermoid carcinoma (MEC). We determined immunohistochemical expression of P27, SKP2, cyclin A, Ki67, phospho-RB, and phospho-ERK in 43 MEC. SKP2 correlated with tumour size, microscopic grade, and a worse prognosis. Cyclin A and Ki67 also predicted prognosis, and were correlated with SKP2. P27 did not predict prognosis. P27 had no inverse relationship with SKP2, and correlated with neither Ki67 nor cyclin A. Instead, P27 high expressers had higher levels of phospho-ERK and phospho-RB. When highly expressed, P27 co-localized with cyclin D1 in the nuclei. Relationships of P27 with ERK and RB and its nuclear co-localization with cyclin D1 favour the hypothesis that P27 is in complexes with cyclin D1. This may explain why P27 in contrast to SKP2 and cyclin A does not correlate with tumour cell proliferation and prognosis.

Molecular classification of mucoepidermoid carcinomas-prognostic significance of the MECT1-MAML2 fusion oncogene

Mucoepidermoid carcinomas (MECs) of the salivary and bronchial glands are characterized by a recurrent t(11;19)(q21;p13) translocation resulting in a MECT1-MAML2 fusion in which the CREB-binding domain of the CREB coactivator MECT1 (also known as CRTC1, TORC1 or WAMTP1) is fused to the transactivation domain of the Notch coactivator MAML2. To gain further insights into the molecular pathogenesis of MECs, we cytogenetically and molecularly characterized a series of 29 MECs. A t(11;19) and/or an MECT1-MAML2 fusion was detected in more than 55% of the tumors. Several cases with cryptic rearrangements that resulted in gene fusions were detected. In fusion-negative MECs, the most common aberration was a single or multiple trisomies. Western blot and immunohistochemical studies demonstrated that the MECT1-MAML2 fusion protein was expressed in all MEC-specific cell types. In addition, cotransfection experiments showed that the fusion protein colocalized with CREB in homogeneously distributed nuclear granules. Analyses of potential downstream targets of the fusion revealed differential expression of the cAMP/CREB (FLT1 and NR4A2) and Notch (HES1 and HES5) target genes in fusion-positive and fusion-negative MECs. Moreover, clinical follow-up studies revealed that fusion-positive patients had a significantly lower risk of local recurrence, metastases, or tumor-related death compared to fusion-negative patients (P = 0.0012). When considering tumor-related deaths only, the estimated median survival for fusion-positive patients was greater than 10 years compared to 1.6 years for fusion-negative patients. These findings suggest that molecularly classifying MECs on the basis of an MECT1-MAML2 fusion is histopathologically and clinically relevant and that the fusion is a useful marker in predicting the biological behavior of MECs.

Selective Immunohistochemical Comparison of Polymorphous Low-Grade Adenocarcinoma and Adenoid Cystic Carcinoma

PURPOSE

Polymorphous low-grade adenocarcinoma (PLGA) is a salivary gland malignancy characterized by indolent growth and a low rate of metastasis. PLGA shares histological features with adenoid cystic carcinoma (ACC), including infiltrating solid and cribriform patterns, presence of cystic spaces, and neurotropism. The degree of polymorphism of PLGA presents diagnostic challenges, particularly in small biopsy specimens. Immunohistochemical reactions to differentiate PLGA from the more aggressive ACC would be extremely valuable but controversy exists in the current literature regarding their utility. This study examines the potential use of c-kit, Ki-67, smooth muscle actin (SMA), and muscle-specific actin (MSA) as ancillary markers for distinguishing PLGA from ACC.

PATIENTS AND METHODS

Medical records of 20 cases of PLGA treated at the Massachusetts General Hospital were reviewed. Patient demographic data and tumor-specific information were elicited. Formalin-fixed paraffin-embedded sections from 10 of these cases and 12 comparison cases of ACC were accessed. The histologic diagnoses were confirmed and immunohistochemical staining using antibodies to c-kit, Ki-67, SMA, and MSA was employed to determine differences in staining.

RESULTS

PLGA showed a significantly weaker immunohistochemical expression of c-kit compared with ACC (P = < .001). Ki-67, correlating with proliferative behavior, was more weakly expressed in PLGA (P = .091). The exuberant myoepithelial component of ACC resulted in stronger staining with SMA and MSA (P = .047; P = .065, respectively).

CONCLUSIONS

Statistically significant immunohistochemical staining patterns using c-kit and SMA in this study support their potential use as markers to differentiate PLGA from ACC in cases where the diagnosis can be challenging.

p53, bcl-2 and Ki-67 expression in adenoid cystic carcinoma of the palate. A clinico-pathologic study of 21 cases with long-term follow-up

Adenoid cystic carcinoma (ACC) is an indolent tumor that pursues a protracted clinical course with recurrences and late metastases. The aim of this study was to investigate immunohistochemically the expression of p53, bcl-2 protein, and Ki-67 in 21 cases of ACC of the palate, all with a minimum of 10 years and a maximum of 22 years of clinical follow-up. These results were also analyzed with regard to different clinical prognoses of the histologic subtypes of ACC. High expression of p53 and bcl-2 was noted in 19 out of 21 ACC cases (90%), in which most tumor cells (from 66% to 99%) proved to be immunopositive. A relation to the histologic types, clinical staging, and survival was not found. Therefore, the high immunoreactivity against these oncoproteins in the same tumor cells suggests that these two oncogenes may be involved since the early stage of carcinogenesis. Loss of function of the p53 protein combined with bcl-2 upregulation might give the tumor cells a double growth advantage, because uncontrolled proliferation is combined with a reduced cell death rate. The interaction with other oncogenes may then trigger a multistep process able to promote tumor progression. The low labeling index Ki-67 was detected in nine out of 21 cases (42%), with a low percentage of tumor cells (from 3% to 15%) being positive, whereas the remaining 12 cases were negative. We found no relation to the histologic types, clinical staging, and survival; however, the low proliferation rate could explain the natural course of tumor.

PCNA, Ki-67 and p53 expressions in submandibular salivary gland tumours

Salivary gland tumours are uncommon with a broad heterogeneity. The most common benign tumour is the pleomorphic adenoma, whereas mucoepidermoid carcinoma and adenoid cystic carcinoma predominate among the malignancies. Most salivary gland tumours occur in the parotid, and consequently clinical and biological data are normally derived from this site. This work describes the expressions of PCNA, Ki-67 and p53 in 15 pleomorphic adenomas, 15 mucoepidermoid carcinomas and 15 adenoid cystic carcinomas of the submandibular gland. Our results showed that all pleomorphic adenomas were negative for p53 and Ki-67 with 66.6% being positive for PCNA. Conversely, p53 was positive in 53% of the mucoepidermoid carcinomas and in 20% of the adenoid cystic carcinomas. Ki-67 was expressed in 47.7% of the mucoepidermoid carcinomas and 40% of the adenoid cystic carcinomas. All malignant tumours were positive for PCNA. These results indicate that the proliferative rate analysed with PCNA and Ki-67 and the expression of p53 in pleomorphic adenoma and adenoid cystic carcinoma of the submandibular gland were similar to those described in the parotid and minor salivary glands. However, mucoepidermoid carcinomas showed higher expression of these markers than those of other salivary glands. This work is the first describing the expression of these immunohistochemical markers exclusively in submandibular salivary gland tumours.

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.

Gallbladder carcinoma: the role of p53 protein overexpression and Ki-67 antigen expression as prognostic markers

BACKGROUND

The overexpression of p53 protein and the expression of Ki-67 antigen may affect the survival of patients with gallbladder carcinoma. This association has been tested in a series of 41 patients with relatively early carcinoma of the gallbladder.

METHODS

Forty-one surgical specimens from patients with a postoperative histological diagnosis of gallbladder carcinoma were studied. All patients were operated by simple cholecystectomy only because the tumours were not advanced and/or their general condition was poor. Patients submitted to radical operations were excluded. p53 expression was calculated from nuclear staining according to the intensity and extent of positive cells, as graded on a scale from 1 to 3; a combined score of >3 was considered as overexpression. Ki-67 expression was calculated by the MIB-I index: the percentage of positively stained tumour cell nuclei out of the total tumour cells counted (n = 1000); >20% of stained cells was considered positive.

RESULTS

Twenty-nine gallbladder carcinomas (71%) overexpressed p53 protein in the cell nuclei. No significant differences were found in relation to cell differentiation on the level of tumour infiltration through the gallbladder wall. Five-year survival of patients with gallbladder carcinoma overexpressing p53 was 17.2%, while survival of patients without p53 overexpression was 30% (not significant). Twenty-four cases (58.5%) were considered positive for the MIB-I index. There were no differences between the grade of cell differentiation and wall infiltration. Five-year survival of the patients with a MIB-I positive index was 9.2% as opposed to 27.7% for those with a negative index (not significant).

CONCLUSIONS

p53 protein nuclear overexpression and Ki-67 protein expression in gallbladder carcinoma were not related to histological differentiation, level of gallbladder wall invasion or patient survival.

Expression of vascular endothelial growth factor in salivary gland carcinomas and its relation to p53, Ki-67 and prognosis

BACKGROUND

Vascular endothelial growth factor (VEGF) has been demonstrated to play an important role in tumor angiogenesis and to influence prognosis in many cancers. But, its significance in salivary gland carcinomas has not been elucidated. The authors investigated the association between VEGF expression and clinicopathological factors, p53, and Ki-67 to verify its validity as a prognostic factor.

METHODS

Surgical specimens from 45 patients with salivary gland carcinoma were examined for VEGF, p53, and Ki-67 expression by immunohistochemical staining. The results were compared with the clinicopathological factors and the relationships were correlated.

RESULTS

VEGF expression was low in 14 cases, moderate in 15 cases, and high in 16 cases. It was significantly correlated with a variety of clinicopathological factors such as TNM stage, perineural and vascular invasion, and recurrence. VEGF showed significant association with the expression of p53 but not with that of Ki-67. Univariate analysis showed that age, gender, lymph node metastasis, vascular invasion, p53, Ki-67, and VEGF expression correlate with prognosis. Multivariate analysis demonstrated that VEGF is an independent prognostic factor for patients with salivary gland carcinomas.

CONCLUSIONS

The results of this study suggest that VEGF expression is correlated with p53 expression and that it may have prognostic value in salivary gland carcinomas.

Expression of HER-2/neu gene and protein in salivary duct carcinomas of parotid gland as revealed by fluorescence in-situ hybridization and immunohistochemistry

AIMS

Salivary duct carcinoma is a highly malignant salivary gland tumour with aggressive clinical behaviour, characterized by histological resemblance to invasive ductal carcinoma of the breast. Amplification of HER-2/neu oncogene and over-expression of its gene product have both prognostic and therapeutic implications in breast cancer. Recent report on salivary duct carcinomas for HER-2/neu using immunohistochemistry (IHC) has shown over-expression in most cases. However, correlation between IHC and molecular genetic analysis of HER-2/neu in salivary duct carcinoma has not yet been performed.

METHODS AND RESULTS

We have now evaluated 11 cases of salivary duct carcinomas for HER-2/neu status using IHC and fluorescent in-situ hybridization (FISH). To our knowledge, this is the first molecular genetic analysis of HER-2/neu in salivary duct carcinoma.

CONCLUSIONS

In immunohistochemistry, over-expression of HER-2/neu protein was identified as distinct membrane staining in most carcinoma cells in all our salivary duct carcinoma cases, while only four cases revealed an amplification of HER-2/neu gene by means of FISH analysis. Both amplified and non-amplified salivary duct carcinomas with strong immunohistochemical staining for HER-2/neu protein were associated with poor clinical outcome for the patients. Apparently, HER-2/neu protein over-expression could also be controlled by mechanisms other than gene amplification. In the group of salivary gland tumours other than salivary duct carcinoma, strong over-expression was detected only in three cases of carcinoma ex pleomorphic adenoma. Thus, over-expression of HER-2/neu protein is also a useful marker of malignant transformation in pleomorphic adenomas.

Mucoepidermoid carcinoma of the salivary glands: clinicopathologic review of 108 patients treated at the National Cancer Institute of Milan

BACKGROUND

Mucoepidermoid carcinoma (MEC) can have a variety of clinical outcomes, but prognosis seems to be related to the tumor grade. The system proposed by Auclair and Goode is useful, and our data lend further support to its application and validity in clinical practice.

METHODS

We have clinicopathologically reviewed 108 cases of MEC originating in major (MASG) and minor (MISG) salivary glands that were treated at the National Cancer Institute of Milan between 1975 and 1995. Following the methods of Auclair and Goode, a quantitative grading system was used. The relationships between clinical and pathologic characteristics and survival rate were investigated.

RESULTS

Twenty-six (44%) cases located in MASG and 19 (39%) cases in MISG were categorized as high-grade tumors. In patients with MASG tumors, the 5-year disease-free survival rate was 22.5% when the tumor was high grade and 97.0% if the tumor was low grade (P <.0001). For patients with a tumor of the MISG, the percentages were 35.3% for high-grade and 80.0% for low-grade tumors (P =.0066).

CONCLUSIONS

Our study confirms that in MEC, tumor grade, subdividing cases into low and high grade by using the criteria delineated by Auclair and Goode, correlates well with prognosis.

Cell proliferation and chromosomal changes in human ameloblastoma

Cell proliferation and chromosomal imbalances, important parameters in relation to tumor progression, were studied in ameloblastoma (n=20), a benign odontogenic tumor of locally recurrent nature. Immunocytochemical staining with MIB-1 antibody and comparative genomic hybridization (CGH) were performed on formalin-fixed paraffin-embedded ameloblastomas. The mean follow-up time was 12.4 years. An MIB-1-index was formed by counting 5000 tumor-cell nuclei in 10-15 randomly chosen high-power fields and calculating percentages of positively stained cells. CGH involved hybridization of FITC-dUTP-labeled tumor DNA with Texas-red-labeled normal DNA. Images were digitally analyzed. The MIB-1-index (range 0-2.51) was low for all tumors. No statistically significant correlation between MIB-1 index and tendency to recurrence was found. Chromosomal aberrations were detected in 2 of 17 cases. The results suggest that formation of an MIB-1 index is not helpful in assessing future clinical behavior of an ameloblastoma and that chromosomal imbalances are uncommon.

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

p27 and Ki-67, a universal cyclin-dependent kinase inhibitor and a proliferative cell marker, respectively, have been useful in predicting clinical aggressiveness in various human tumors. We studied clinicopathologic significance of these molecules in mucoepidermoid carcinoma of the intraoral minor salivary gland. Expression of p27 and Ki-67 was assessed immunohistochemically in primary mucoepidermoid carcinomas from 31 patients without distant metastasis at surgery. Correlation each of p27 and Ki-67 expression was analyzed with various clinicopathologic parameters including age, sex, primary tumor site, tumor size, nodal metastasis, clinical stage, and histologic grade. The latter was evaluated using a point-scoring scheme of Auclair et al. that consists of five histologic factors (intracystic component, neural invasion, necrosis, mitosis, and anaplasia). p27 expression was correlated inversely with histologic grade (P =.007), but with none of other factors. When the correlation of p27 expression was further examined with each of the histologic factors, it was correlated significantly with intracystic component, but not with neural invasion, necrosis, mitosis, or anaplasia. Ki-67 expression was correlated significantly with histologic grade only in the clinicopathologic factors (P <.0001), and in the histologic factors, with necrosis, mitosis, and anaplasia. Multivariate prognostic analyses were performed to identify independent risk factors for both disease-free and overall survivals. Large tumor size (P =.031, relative risk = 5.5) and low p27 expression (P =.012, relative risk = 5.2) were risk factors for worse disease-free survival. Low p27 expression (P =.015, relative risk = 15.2) was selected as a risk factor for worse overall survival. Other factors including age, sex, tumor site, nodal status, clinical stage, histologic grade, and Ki-67 did not emerge as independent risk factors in either prognostic analysis. These data suggest that p27 may be useful in estimating prognosis of the patients who have mucoepidermoid carcinoma of the intraoral minor salivary gland.

[Cell proliferation in salivary gland tumors]

Previous studies on cell proliferation in salivary gland tumors have shown the utility of immunostain with MIB1 in the differential diagnosis and prognosis of these neoplasms. We have carried out a study of 39 salivary gland tumors (17 benign), from different histological lineages. The immunocytochemical method used was the streptavidin--biotin--peroxidase complex which used the MIB1 monoclonal antibody. Benign tumors showed a low cell proliferation rates, below 5% with an overall average of 1.9%. The malignant tumors presented higher rates, with a middle value of 17.85%. Epidermoid carcinomas had the higher cell proliferation rates, with an average of 43%. In adenoid cystic carcinomas, we have observed that proliferation was greater at the peripheral level of tumor nests and cell surrounding the cystic structures. Neoplasms of low grade of malignancy presented lower cell proliferation rates. The MIB1 immunostain allowed to reach a differential diagnosis between pleomorphic adenoma and adenoid cystic carcinoma, specially in those cases in which there could be any doubt.

Low expression of p27(Kip1) in advanced mucoepidermoid carcinomas of head and neck

BACKGROUND

p27(Kip1), a cyclin-dependent kinase inhibitor, negatively regulates the G1 phase progression of the cell cycle by binding to the cyclin E/cyclin-dependent kinase 2 complex. This study was done to investigate the expression of p27(Kip1) in mucoepidermoid carcinomas and its usefulness as an indicator in tumor progression, aggressiveness, and prognosis.

METHODS

Thirty-one patients with mucoepidermoid carcinomas who had surgical resection were studied retrospectively. Clinicopathologic features, including histologic types, T stage, nodal status, perineural invasion, overall AJCC stage, and survival data, were obtained from medical records. Immunohistochemical staining with monoclonal antibodies against p27(Kip1) was performed on the formalin-fixed, paraffin-embedded specimens from each patient. The percentage of tumor cells expressing p27(Kip1) (labeling index) was evaluated by counting 1000 cells per slide in at least four different areas and comparing with the patients' clinicopathologic features and survival rates.

RESULTS

Significant correlation was found between low p27(Kip1) expression and tumors with high-grade, advanced T stages, positive nodal status, and advanced clinical stages (p =.001 for all) except perineural invasion. Multivariate analysis indicated that p27(Kip1) expression (p =.030) was the most significant, and gender (p =.048) was the next significant predictor of overall survival among the variables. Also patients with low p27(Kip1) expression showed poor prognosis (p =.002).

CONCLUSIONS

We suggest that p27(Kip1) is a reliable independent marker of tumor progression, invasiveness, and prognosis in the mucoepidermoid carcinomas.

Application of immunohistochemistry to the diagnosis of salivary gland tumors

A panel of antibodies composed of the cytokeratins (CKs), vimentin, and actin was applied to 114 minor salivary gland tumors to evaluate its diagnostic value. The results revealed that luminal cells of intercalated duct-like structures, such as those seen in pleomorphic adenoma, basal cell adenoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma, expressed CKs 7, 8, 14, and 19. The outer cells of these structures exhibited vimentin or vimentin plus muscle-specific actin, but rarely CK14, which is seen particularly in pleomorphic adenoma, in the tubular type of basal cell adenoma, and seldom in the tubular type of adenoid cystic carcinoma. Modified myoepithelial cells of pleomorphic adenoma and myoepithelioma exhibited a variable immunoprofile. CKs 7 and 8 were also observed in acinar cell adenocarcinoma and polymorphous low-grade adenocarcinoma with vimentin in the latter. CK13 was expressed only by canalicular adenoma and mucoepidermoid carcinoma cells. This study showed that the panel of antibodies employed is effective in distinguishing among salivary gland tumors.

Mucoepidermoid carcinoma of salivary glands in children and adolescents: assessment of proliferation markers

Malignant neoplasms represent one-third of all pediatric salivary gland tumors. Mucoepidermoid carcinoma (MEC) composes 51% of malignant tumors and 16% of all salivary gland neoplasms in pediatrics. Prognostic factors in MEC in pediatric patients have not been well defined. Histopathologic features, clinical outcomes and proliferation markers in 26 pediatric patients (median age 11 years; 19F:7M) with salivary gland MECs were evaluated retrospectively. MEC histocytologic grading used a three-tiered system. Proliferation was assessed by determining the percentage of tumor cells immunoreactive for PCNA and Ki-67. Tumor site was 16 parotid, eight submandibular, one base of tongue and one maxillary lip. Median tumor size was 2.5 cm (range 1.5-5 cm). MEC grade was nine low grade (LG), 15 intermediate grade (IG) and two high grade (HG). Metastatic disease and capsular invasion occurred in five cases, while perineural invasion was noted in three cases. Mean percentage of tumor cells immunoreactive for proliferation markers is as follows: PCNA: LG 9%, IG 17%, HG 32%; and Ki-67: LG 7%, IG 12%, HG 26%. Treatment was surgical in 21 cases, and surgery with chemotherapy and radiotherapy in five cases. Two patients with high grade MECs died of disease (21, 44 months). Twenty-four patients had no evidence of disease at a median follow-up of 104 months (range 30-298 months). MECs were second malignancies in two children with prior radiotherapy and chemotherapy for leukemia and histiocytosis. Low and intermediate grade salivary gland MECS in a pediatric population may have a favorable outcome when compared with high grade MECs. Proliferation markers appear to be linked to histocytologic MEC grade and may provide information regarding biologic behavior of salivary gland MECs in children and adolescents.

Apoptosis and apoptotic-related factors in mucoepidermoid carcinoma of the oral minor salivary glands

The oncoproteins Bcl-2 and Bax, the tumor suppressor gene product p53, TUNEL (TdT [terminal deoxynucleotidyl transferase] dUTP nick end-labeling) and the cell-cycle antigen Ki-67 were studied in 71 cases of mucoepidermoid carcinoma originating in the oral minor salivary glands. Grade I tumors had higher expression of Bcl-2 than Grade II and III tumors (chi2 test, 0.01<P<0.025) and the Bcl-2-positive group had a higher survival rate than the Bcl-2-negative group (generalized Wilcoxon, P = 0.00051). Patients with strong TUNEL positivity had a higher survival rate than those with either weak positivity or negativity (generalized Wilcoxon, P = 0.047). The expression of p53 and TUNEL had a positive correlation (P = 0.0315). Grade II and III tumors had a higher frequency of positive Ki-67 expression than Grade I tumors (chi2 test, 0.01<P<0.025) and patients with Ki-67-negative tumors had better survival than patients with Ki-67-positive tumors (generalized Wilcoxon, P = 0.000099). This study showed that Bcl-2 proteins, p53 protein, TUNEL and Ki-67 are potentially useful prognostic markers for survival in patients with mucoepidermoid carcinoma of the oral minor salivary glands.