Expression of the multidrug resistance protein MRP and the lung-resistance protein LRP in nasal NK/T cell lymphoma: further exploring the role of P53 and WT1 gene

Abstract

Nasal NK/T-cell lymphoma (NKTL) is relatively common in the adult men of Asia. Many patients with nasal NKTL have poor response to therapy. Some of them show P-glycoprotein over-expression. To investigate the expression of other multidrug resistance proteins (MDR) and possible regulatory factors in nasal NKTL, the clinical and pathological features are described. Thirty Chinese adults with nasal NKTL are presented. Immunohistochemical study was carried out to detect multidrug resistance-associated protein 1 (MRP) and lung resistance-related protein (LRP). The association between possible regulatory proteins (P53 and WT1) and MDR were explored. In situ hybridisation for Epstein-Barr virus (EBV) detection, polymerase chain reaction assay for T-cell receptor gene and direct sequencing for the P53 gene were performed. Seven (23.3%) and eight (26.7%) patients showed immunoreactivity of MRP and LRP, respectively. Positive staining for both markers was identified in 6.7% (2 cases). The EBV was detected in most cases (97%). Twenty-six (86.7%) cases expressed positive nuclear staining of P53. However, of the cases analysed for P53 mutation, none showed a mutaion at the hot spots studied. WT1 protein was not detected in the nasal NKTL. Our study reports expression of MRP and LRP in nasal NKTL. The over-expression of P53 is probably associated with high incidence of EBV infection and unlikely a regulatory protein for the expression of MRP and LRP. Further studies are necessary to validate the association between P53 mutation and expression of MRP and LRP in nasal NKTL.