Prognostic Significance of Expression of Glutathione S-Transferase-pi and Multidrug Resistance-Associated Protein in Nasopharyngeal Carcinoma / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: For the treatment of nasopharyngeal carcinoma (NPC), radiation therapy is a primary option. Because of distant metastasis and the high incidence of a locoregional failure following radiotherapy, the combined treatment modality with chemotherapy is applied, although resistance to chemotherapy makes chemotherapy less effective. The Cisplatin-based chemotherapy has been widely used in the field of nasopharyngeal cancer. The Cisplatin resistance is known to be caused by the multidrug resistance-associated protein (MRP), which is one of the drug-export pumps and the glutathione S-transferase (GST)-pi which catalyzes the conjugation of the GSH (glutathione) and the cisplatin. The aim of this study is to determine the predictive value of GST-pi and MRP upon the response to cisplatin in nasopharyngeal carcinoma. SUBJECTS AND METHOD: We analyzed tumor tissues from 49 cases of paraffin block specimens which were diagnosed with NPC and treated at Chonnam National University Hospital. The immunohistochemical study for the GST-pi and the MRP was performed with paraffin block specimens of nasopharyngeal cancers. RESULTS: In the GST-pi, the relationship between the early stage (64.3%) and the advanced stage (91.4%) was statistically significant (p=0.020). The expression of the GST-pi and the MRP had no relationship with the clinical factor, the response to chemotherpy and the survival rate. CONCLUSION: Because the expression of the GST-pi and the MRP in the nasopharyngeal carcinoma could not predict the response to chemotherapy. So the efforts to find the predictive value of the chemotherapy are needed.