The present invention relates to methods for predicting the outcome of therapeutic intervention in cases of leukemia, especially acute lymphoblastic leukemia in children and adults. The present invention evaluates a gene expression profile and identifies prognostic genes of cancers, in particular leukemia, more particularly B-precursor acute lymphoblastic leukemia (ALL). The present invention provides a method of determining prognosis of leukemia, in particular, acute lymphoblastic leukemia, more particularly B-precursor ALL and predicting therapeutic outcome of a patient. The method comprises the steps of first establishing the threshold value of at least three prognostic genes of leukemia, preferably at least eight prognostic genes, or preferably, as many as 26 prognostic genes. Then, the amount of the prognostic gene(s) from a leukemia patient is determined. The amount of the prognostic gene present in that patient is compared with the established threshold value of the prognostic gene(s) which is indicative of therapeutic success or failure, whereby the prognostic outcome of the patient is determined/predicted.
 The invention described in this application was made with support from the National Institutes of Health (National Cancer Institute), Grant No. NIH NCI U01 CA88461; and under a contract from the Department of Energy, Contract No. DE-AC04-94AL85000. The U.S. Government retains certain rights in this invention.