CHEK1 and acute lymphoblastic leukemia: In order to identify gene expression changes specifically correlated with Chk1 inhibition and to better elucidate the mechanism of action of Chk1 inhibitor, gene expression profiling (GEP) analysis was performed by microarray on treated B/T-ALL cell lines (BV-173, SUP-B15, REH, NALM-6, NALM-19, MOLT-4, RPMI-8402, and CCRF-CEM) and on their untreated counterparts (DMSO 0.1 %) after 24 h of drug exposure.