[The clinical significance of lung resistance protein (LRP) gene expression in patients with acute leukemia].

OBJECTIVE: To investigate the relationship between the expression of lung resistance protein (LRP) gene and drug resistance in patients with acute leukemias (AL). METHODS: Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR)was used to examine the expression of LRP gene in AL patients and 15 normal subjects. Beta(2) microglobulin (beta(2)MG) was used as internal reference. LRP/beta(2)MG ratio >or= 0.3 was defined as LRP positive. RESULTS: The positivity percentage of LRP gene expression in newly diagnosed group was 32.4%. The first complete remission rate was 84.0% and 33.0% in LRP negative and LRP positive patients, respectively. The difference was significant (P < 0.005). The expression level of LRP mRNA and the positivity percentage of LRP in relapsed/refractory group were significantly higher than that in newly diagnosed group (P < 0.01). The expression level of LRP gene in normal subjects and long-term survival groups was very low and correlated with FAB subtypes. The mdr-1 gene was examined simultaneously in 61 AL patients. No significant correlation was found between the expression of LRP and mdr-1 gene (P > 0.5). Coexpression of LRP and mdr-1 genes in the same AL patient might result in the worst prognosis. CONCLUSION: High expression of LRP gene leads to clinical drug resistance and is an unfavorable factor to AL patients of prognosis.