We analyzed surface antigens, multidrug resistance (MDR) parameters (PGP, MRP, LRP), tissue infiltration parameters (CD18, CD44, VCAM, MMP2), receptors for colony stimulating factors (G-CSFr, GM-CSFr) and cell cycle parameters (Ki-67, topoisomerase IIalpha) in 86 patients with acute lymphoblastic leukemia (ALL). LRP, PGP and CD18 were associated with poor clinical outcome, and LRP expression was related with CD18, CD44 and G-CSFr. Of the cell cycle parameters, Ki-67 (+) fraction was increased in ALL with hepato-splenomegaly and extramedullary involvement. In conclusion, analysis of LRP, PGP, CD18 and Ki-67 could be helpful to predict the clinical behavior of ALL.