Application of Two Different Clones of Vimentin to the Diagnosis of Salivary Gland Tumors

Utility of smooth muscle actin and CD117 as reliable markers in the diagnosis of salivary gland neoplasms

Objective:

The aim of this study is to analyze the utility of immunohistochemical markers such as CD117 and smooth muscle actin (SMA) in the diagnosis of various benign and malignant salivary gland neoplasms.

Materials and Methods:

The study comprises 17 samples categorized into three groups: Group I consisted of 5 histopathologically normal salivary gland tissue; Group II comprised 7 cases, of which 3 cases were pleomorphic adenoma, 3 cases were myoepithelioma and 1 case was Warthin's tumor; and Group III consisted of 5 cases, of which 1 was mucoepidermoid carcinoma and 4 cases were adenoid cystic carcinoma. The selected cases were subjected to immunohistochemistry (IHC) procedure to assess the expression pattern of CD117 and SMA.

Results:

In SMA, 85.8% showed severe-to-moderate intense expression among the tumor cells in benign salivary gland tumor. All the 5 malignant tumors showed the expression of SMA and 3 cases demonstrated severe expression among the tumor cells. An intense expression pattern of SMA was observed in both benign and malignant neoplasms in the periphery and stromal components of the tumor. Only two cases were positive for CD117, and connective tissue components were completely negative in both malignant and benign salivary gland neoplasms.

Conclusion:

Alpha-SMA can be utilized as reliable IHC markers for salivary gland neoplasms due to its diagnostic importance in tumors with myoepithelial origin indicative of the histogenesis of salivary gland tumors.

Immunohistochemical evaluation of salivary gland tumors differentiation and proliferation by using calponin and telomerase

Background

Salivary gland tumors are a heterogeneous group of lesions with diverse histological features. Hence they are considered as a diagnostic challenge for the pathologist. Myoepithelial cells are considered as a key in the morphogenetic process, with diverse differentiation in various salivary gland tumors. Calponin is an actin filament- associated protein that represents a sensitive marker of myoepithelial cells. Telomerase is a ribonucleoprotein that adds telomere repeats at the end of chromosomes in order to prevent replicative senescence. It has a key role in cellular immortality and tumorgenesis of various tumors. This study evaluates the immunohistochemical expression of calponin and telomerase in various salivary gland tumors.

Methods

This retrospective study involved 30 formalin fixed paraffin embedded blocks of salivary gland tumors. The immunohistochemical staining and evaluation of subcellular localization, pattern, intensity, and distribution for calponin and immune scoring for telomerase were done. The statistical analyses of data were conducted by Chi-square and ANOVA-test, a P-value of <0.05 was considered significant.

Results

Calponin showed expression at the periphery of acini and intercalated ducts in the normal salivary gland. It revealed cytoplasmic expression in 83.3% of benign tumors. The pleomorphic adenoma showed a diffuse pattern of staining (85.7%), strong intensity (64.3%), and mixed distributions (57.1%). The diffuse pattern of calponin was seen in all cases of mucoepidermoid, polymorphous low-grade adenocarcinoma and epithelial-myoepithelial carcinoma (100%). Telomerase revealed negative expression in the normal salivary gland. Pleomorphic adenoma illustrated high telomerase expression in score 2 and score 3 (93.3%). Telomerase immune scoring is significantly related to the benign tumors as P value was 0.03. Both polymorphous low grade and epithelial-myoepithelial carcinoma were detected only in score 3. Finally, the mean level of telomerase activity was slightly higher in malignant tumors than benign ones with non-significant relation as P value was 0.6.

Conclusions

Calponin showed high diffuse staining with altered distribution in salivary gland tumors, which might give an additional role for this marker in the identification of luminal immuno-modified neoplastic cells. Telomerase is considered as a useful marker in identifying proliferation capacity of salivary gland tumors and is remarkably more detected in malignant salivary gland tumors.

Review and Updates of Immunohistochemistry in Selected Salivary Gland and Head and Neck Tumors

Context

Immunohistochemistry is a useful tool for diagnosing salivary gland and head and neck tumors.

Objective

To review immunohistochemical markers, which can aid in the diagnosis of selected salivary gland and head and neck tumors.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

Salivary gland and head and neck tumors include a large diverse group of tumors with complex and overlapping histologic features. Immunohistochemistry plays an important role in resolving the differential diagnosis of some salivary gland and head and neck tumors and can provide information for the prognosis of certain tumors.

Immunohistochemical expression of vimentin, calponin and HHF-35 in salivary gland tumors

Myoepithelial cells present a complex immunophenotype, with the expression of proteins varying according to the stage of normal or neoplastic differentiation of the cell. In order to evaluate the immunohistochemical markers expressed by these cells, a panel of antibodies composed of vimentin, calponin and HHF-35 was applied to 28 salivary gland tumors. The results demonstrated a higher percent sensitivity of vimentin and calponin compared to HHF-35. However, calponin and HHF-35 presented a focal labeling pattern in contrast with the diffuse distribution of vimentin. The cells predominantly stained by all tested antibodies included nonluminal cells in duct-like and tubular structures, such as those seen in pleomorphic adenomas and adenoid cystic carcinomas, as well as cells in the cords and nests of polymorphous low-grade adenocarcinomas and peripheral cells of sheets and nests of myoepitheliomas. In conclusion, the combination of calponin and vimentin is suggested for the identification of myoepithelial cells in salivary gland tumors.