Gene expression of BAALC, CDKN1B, ERG, and MN1 adds independent prognostic information to cytogenetics and molecular mutations in adult acute myeloid leukemia.

Expression of BAALC, ERG, and MN1 is associated with outcome in normal karyotype acute myeloid leukemia (AML). In this study, the expression of these markers and of EVI1 and CDKN1B was determined using oligonucleotide microarrays in 286 AML comprising all cytogenetic groups. Higher expression of each gene was associated with an inferior outcome: CDKN1B, median overall survival (mOS): 14.9 months vs. not reached (nr), P = 0.005, median event-free survival (mEFS): 9.7 vs. 31.0 months, P = 0.013; BAALC, no impact on OS, mEFS: 6.2 vs. 13.0 months, P = 0.03; ERG: mOS: 12.5 months vs. nr, P = 0.002, mEFS: 8.1 vs. 15.7 months, P = 0.001; MN1: mOS: 12.3 months vs. nr, P = 0.004, mEFS: 8.1 vs. 16.7 months, P = 0.001. A multivariate analysis revealed an independent impact on OS for CDKN1B, ERG, and MN1 expression. A novel score based on BAALC, CDKN1B, ERG, and MN1 expression had an impact on OS and EFS independent of cytogenetics and age. A score taking into account gene expression and karyotype allowed the separation of four prognostic groups with significant differences in OS and EFS (OS at 2 years: 90.4%, 56.4%, 34.0%, 12.6%; mEFS: n.r., 18.1 months, 8.7 months, 2.5 months). The impact on outcome of this score was independent of NPM1mut/FLT3-ITD- status, MLL-PTD, and age.