title: Serum concentrations of nitrite and malondialdehyde as markers of oxidative stress in chronic myeloid leukemia patients treated with tyrosine kinase inhibitors.
abstract: BACKGROUND
  Chronic myeloid leukemia is a neoplasm characterized by clonal expansion of hematopoietic progenitor cells resulting from the (9:22)(q34,11) translocation. The tyrosine kinase abl fusion protein,the initial leukemogenic event in chronic myeloid leukemia, is constitutively activated thus inducing the production of reactive oxygen species. Of particular relevance is the fact that an increase in reactive oxygen species can facilitate genomic instability and may contribute to disease progression.
  
  
  OBJECTIVE
  To evaluate oxidative stress by determining the levels of malondialdehyde and nitrite in chronic myeloid leukemia patients under treatment with 1st and 2nd generation tyrosine kinase inhibitors monitored at a referral hospital in Fortaleza, Ceará.
  
  
  METHODS
  A cross-sectional study was performed of 64 male and female adults. Patients were stratified according to treatment. The levels of malondialdehyde and nitrite were determined by spectrophotometry. Statistical differences between groups were observed using the Student t-test and Fisher's exact test. The results are expressed as mean ± standard error of mean. The significance level was set for a p-value < 0.05 in all analyses.
  
  
  RESULTS
  The results show significantly higher mean concentrations of nitrite and malondialdehyde in chronic myeloid leukemia patients using second-generation tyrosine kinase inhibitors compared to patients on imatinib.
  
  
  CONCLUSIONS
  It follows that chronic myeloid leukemia patients present higher oxidative activity and that the increases in oxidative damage markers can indicate resistance to 1st generation tyrosine kinase inhibitors.
authors.affiliation: Universidade Federal do Ceará - UFC, Fortaleza, CE, Brazil.
authors.forename: Maria Juracy
authors.initials: MJ
authors.lastname: Petrola
authors.forename: Alana Joselina Montenegro
authors.initials: AJ
authors.lastname: de Castro
authors.forename: Maria Helena da Silva
authors.initials: MH
authors.lastname: Pitombeira
authors.forename: Maritza Cavalcante
authors.initials: MC
authors.lastname: Barbosa
authors.forename: Acy Telles de Souza
authors.initials: AT
authors.lastname: Quixadá
authors.forename: Fernando Barroso
authors.initials: FB
authors.lastname: Duarte
authors.forename: Romelia Pinheiro
authors.initials: RP
authors.lastname: Gonçalves
keywords: Leukemia, myelogenous, chronic, BCR-ABL positive; Malondialdehyde; Oxidative stress; Protein-tyrosine kinases