Significance of lung resistance-related protein in the clinical outcome ofacute leukaemic patients with reference to P-glycoprotein

Lung resistance-related protein (LRP) overexpression in leukaemic blast cel ls from acute leukaemia patients and the effect of LRP or P-glycoprotein (P -gp) on the clinical outcome of acute leukaemia were investigated individua lly by dividing patients into four groups. The complete remission rate of g roup I (LRP and P-gp both negative) was 81.7%, group II (only LRP positive) 87.5%, group III (only P-gp positive) 87.1% and group IV (LRP and P-gp bot h positive) 40.0%. There were no statistical differences between group I an d groups II or III, but a significant difference was observed between group s I, II or III and group IV. Median overall survival in group IV was signif icantly shorter (4.6 months) than in groups I, II or III, although no signi ficant differences were observed between group I and groups II or III (18.9 , 20.5 and 31.8 months). There was a tendency for disease-free survival in group III to be longer than that in groups I, LI or IV. The reasons for the se findings are discussed. Our present results indicate that the co-existen ce of LRP and P-gp strongly influenced the effectiveness of induction chemo therapy and long-term prognosis, whereas the isolated presence of LRP or P- gp did not.