Mcl-1 Expression Is Up-Regulated in Malignancies of the Parotid Gland

The anti-apoptotic protein Mcl-1 is highly expressed in various types of malignant tumors. Overexpression is reported to correlate with poor prognosis and disease progression. We report the expression levels of Mcl-1 in tumor samples of the parotid gland. A retrospective study containing 108 patients was performed. A tissue microarray of six malignancies of the parotid gland and pleomorphic adenoma as control was constructed. Parotid gland tumor samples were immunohistochemically stained for Mcl-1 and expression intensities were assessed. Statistical analysis included correlation to patients' clinical data and comparison of malignancies to the adenoma. All malignancies had significantly higher expression of Mcl-1 than the pleomorphic adenomas. The intensity, however, had no significant correlation to overall survival. Our immunohistochemical findings indicate that parotid gland malignancies produce high levels of Mcl-1 protein. Therefore, Mcl-1 might serve as a predictive co-marker in tumors of the parotid gland.