title: Multiple drug resistance protein (MDR-1), multidrug resistance-related protein (MRP) and lung resistance protein (LRP) gene expression in childhood acute lymphoblastic leukemia.
abstract: BACKGROUND
  Despite the advances in the cure rate for acute lymphoblastic leukemia, approximately 25% of affected children suffer relapses. Expression of genes for the multiple drug resistance protein (MDR-1), multidrug resistance-related protein (MRP), and lung resistance protein (LRP) may confer the phenotype of resistance to the treatment of neoplasias.
  
  
  OBJECTIVE
  To analyze the expression of the MDR-1, MRP and LRP genes in children with a diagnosis of acute lymphoblastic leukemia via the semiquantitative reverse transcription polymerase chain reaction (RT-PCR), and to determine the correlation between expression and event-free survival and clinical and laboratory variables.
  
  
  METHODS
  A retrospective clinical study.
  
  
  METHODS
  Laboratory of Pediatric Oncology, Department of Pediatrics, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
  
  
  METHODS
  Bone marrow aspirates from 30 children with a diagnosis of acute lymphoblastic leukemia were assessed for the expression of messenger RNA for the MDR-1, MRP and LRP genes by semi-quantitative RT-PCR.
  
  
  RESULTS
  In the three groups studied, only the increased expression of LRP was related to worsened event-free survival (p = 0.005). The presence of the common acute lymphoblastic leukemia antigen (CALLA) was correlated with increased LRP expression (p = 0.009) and increased risk of relapse or death (p = 0.05). The relative risk of relapse or death was six times higher among children with high LRP expression upon diagnosis (p = 0.05), as confirmed by multivariate analysis of the three genes studied (p = 0.035).
  
  
  CONCLUSIONS
  Cell resistance to drugs is a determinant of the response to chemotherapy and its detection via RT-PCR may be of clinical importance.
  
  
  CONCLUSIONS
  Evaluation of the expression of genes for resistance to antineoplastic drugs in childhood acute lymphoblastic leukemia upon diagnosis, and particularly the expression of the LRP gene, may be of clinical relevance, and should be the object of prospective studies.
authors.affiliation: Laboratory of Pediatric Oncology, Department of Pediatrics, University Hospital, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil. elvisvalera@hotmail.com
authors.forename: Elvis Terci
authors.initials: ET
authors.lastname: Valera
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Scrideli
authors.forename: Rosane Gomes de Paula
authors.initials: RG
authors.lastname: Queiroz
authors.forename: Bianca Maria Ortelli
authors.initials: BM
authors.lastname: Mori
authors.forename: Luiz Gonzaga
authors.initials: LG
authors.lastname: Tone
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000293:Adolescent; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D004812:Epidemiologic Methods; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000235:genetics*; D019450:Genes, MDR / Q000235:genetics; D006801:Humans; D007223:Infant; D008297:Male; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D009363:Neoplasm Proteins / Q000235:genetics*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020394:Vault Ribonucleoprotein Particles / Q000235:genetics*; D000099187:Major Vault Protein
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein