title: Expression of multidrug resistance-related markers in primary neuroblastoma.
abstract: BACKGROUND
  Multidrug resistance is associated with a poor prognosis in various human cancers. However, the clinical significance of the expression of multidrug resistance-related markers in neuroblastoma is still on debate. In this study, the effect of the expression of p-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and lung resistance protein (LRP) in neuroblastoma was evaluated.
  
  
  METHODS
  The streptavidin-biotin immunoperoxidase (SP) technique was used to evaluate the expression of P-gp, MRP, and LRP in 70 cases of untreated primary neuroblastoma.
  
  
  RESULTS
  The frequencies of the expression of P-gp, MRP, and LRP were 61.4%, 38.6%, and 24.3%, respectively. A significant positive correlation was observed between P-gp and MRP expression (P=0.001), as well as between LRP and MRP expression (P=0.01). The rates of expression of P-gp and MRP were higher in tumors from patients aged greater than one year old than in tumors from patients aged less than 1 year old at time of diagnosis (P=0.01 and 0.018, respectively). MRP expression in tumors that had metastasized was significantly more frequent than in tumors that had not metastasized (P=0.015). The expression of all tested proteins showed a significant relationship with whether or not the tumor had differentiated (P=0.006, 0.000 or 0.001, respectively). MRP expression was significantly associated with a reduction in both median survival time and 2-year cumulative survival (P=0.02). By contrast, P-gp and MRP expression did not correlate with survival. According to Cox regression analysis, only the co-expression of P-gp and MRP had significant prognostic value (relative hazard, 3.513, P=0.033).
  
  
  CONCLUSIONS
  The intrinsic, multidrug resistance of neuroblastoma involves the combined effects of P-gp, MRP, and LRP. MRP expression may be an important factor determining prognosis in neuroblastoma.
authors.affiliation: Department of Pathology, No. 2 Clinical College, China Medical University, Shenyang 110004, China. lvqjie@163.com
authors.forename: Qing-jie
authors.initials: QJ
authors.lastname: Lu
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.forename: Jin-hua
authors.initials: JH
authors.lastname: Zhang
authors.forename: Xiao-han
authors.initials: XH
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.forename: Wei-guo
authors.initials: WG
authors.lastname: Jiang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000032:analysis*; D009363:Neoplasm Proteins / Q000032:analysis*; D009447:Neuroblastoma / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D011379:Prognosis; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein