Histopathological Investigation of Nuclear Y-box Binding Protein-1 Expression in Salivary Gland Carcinoma.
Histopathological diagnosis of salivary gland carcinoma is relatively difficult because of the low frequency and variety of histopathological types of this cancer. There is at present no effective immunohistochemically identifiable prognostic marker in cases of salivary gland carcinoma. Since nuclear expression of Y-box binding protein-1 (YB-1) is known to be correlated with the tumor aggressiveness and poor prognosis in various types of cancers, this study was aimed at investigating the relationship between the expression of YB-1 and other relevant proteins (androgen receptor (AR), epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor type 2 (HER2)) and the histopathological grade, clinical parameters and prognostic factors in patients with salivary gland carcinoma.Immunohistochemistry was performed to evaluate the expression of YB-1, AR, EGFR and HER2 proteins in 66 cases of salivary gland carcinoma. The histopathological types included salivary duct carcinoma (n=37), mucoepidermoid carcinoma (n=24) and adenocarcinoma not otherwise specified (NOS) (n=5).The expression rate of YB-1 protein was 83.7% in salivary duct carcinoma and 80% in adenocarcinoma NOS. The expression of YB-1 and HER2 were correlated with the presence of lymph node and distant metastasis (p<0.05). AR expression was correlated with the presence of lymph node metastasis (p<0.05). Using univariate survival analysis, YB-1 and HER2 expressions were identified as being correlated with the overall and disease-free survival rates (p<0.05). Furthermore AR expression was identified as being correlated with the disease-free survival rate (p<0.05).Nuclear expression of YB-1 in salivary gland carcinomas appears to be useful for the histopathological diagnosis of malignancy. Into the clinical significance of immunohistochemistry for AR and HER2 expressions, nuclear YB-1 expression appears to be a prognostic factor in cases of salivary gland carcinoma.