Increased OPN expression is associated with poor OS in AML. (A) Scatterplot showing OPN expression determined by quantitative RT-PCR in 4 normal CD14⁺ monocyte controls and 95 diagnostic samples from consecutive patients with AML collected at the RAH of which 60 were treated with induction chemotherapy. The horizontal lines indicate the median expression of OPN (0.23 AU). (B) Scatterplot of the range and median of OPN expression for various FAB classifications for all patients analyzed (95 RAH plus 35 Kunamoto normal karyotype patients). There is a significant difference in median OPN expression between FAB M3 and M4 or M5 subgroups (P = 0.01, Kruskal-Wallis test; P < .05, Dunn multiple comparisons test). (C) Kaplan-Meier log-rank analysis of all patients from RAH who underwent standard induction chemotherapy, excluding acute promyelocytic leukemia (APML; M3; n = 52). Taking a cutoff of 0.23 AU (median; split panel A), patients were divided into either high OPN expressers (> 0.23 AU) or low OPN expressers (< 0.23 AU). (D) Scatterplot showing the range and median of OPN expression for cytogenetically normal AML patient samples obtained at RAH (n = 25) and Kunamoto (n = 35), which were analyzed for OS (E). (E) Kaplan-Meier survival curves for the combined patients with normal cytogenetic AML shown in panel D after standard induction chemotherapy (n = 60), comparing high versus low OPN expression as determined by median split of each cohort as shown in panel D. High OPN is associated with poor OS (median, 384 days) compared with low OPN (median, 1017 days; P = .01). (F) Scatterplot comparing OPN expression in patients with cytogenetically normal AML analyzed in panel E for which FLT3 mutation status had been determined (ITD or D835 mutation; n = 37). There was no difference in median OPN expression between the 2 groups (n = 37; P = .2, Mann-Whitney U test). (G) Two patients for whom cryopreserved diagnosis and relapse samples were available were examined for OPN expression by quantitative RT-PCR. A significant increase in OPN expression was observed in both patients at relapse (P < .05, Mann-Whitney U test).