BAALC and ERG expression in acute myeloid leukemia with normal karyotype: impact on prognosis

Cytogenetic aberrations are important prognostic factors in acute myeloid leukemia (AML). About 45% of de novo AML lack cytogenetic abnormalities, so identification of predictive molecular markers might improve therapy. We studied the prognostic impact of brain and acute leukemia, cytoplasmic (BAALC) and ETS-related gene (ERG) expression in AML with normal karyotype. Pretreatment bone marrow samples from 30 cytogenetically normal AML patients were analysed for BAALC and ERG expression using real time RT-PCR. The patients were dichotomized at BAALC and ERG mean expression into low and high expression. BAALC showed high expression in 70% of patients and its expression did not correlate with the clinical parameters of patients. ERG was high in 33.3% of patients and its expression was associated with lower ages and higher white cell counts. With follow-up for 2 years, patients with high BAALC and high ERG had low rates of clinical remission (P < 0.005) and inferior overall survival (OS) (P < 0.001 and <0.002 for BAALC and ERG respectively). No significant association was observed between the increase in BAALC and ERG expression (P = 0.398). Multivariable analysis confirmed high BAALC expression as an independent risk factor for OS. Overexpression of BAALC and ERG either separate or concomitant predict adverse clinical outcome and may define important risk factor in cytogenetically normal AML.