In the first group we studied the following two-class datasets: a) acute lymphoblastic leukemia versus acute myeloid leukemia [23], b) two different myeloid leukemia types defined by the presence of two oncogeneic fusion proteins (AML1-ETO, t(8;21) versus RAR-PML, t(15;17)) [43]. The gene discussed is RARA; the disease is acute myeloid leukemia.