Transformation assays of the myeloblasts from the leukemic mice. (A) Colony assays of splenocytes from leukemic mice in methylcellulose medium-containing cytokines. The mean values ± SD of 3 independent assays are shown. (B) Leukemic blast cell colonies formed in methylcellulose containing IL-3 and GM-CSF (left; original magnification, × 60) and May-Giemsa staining of cells from these colonies (right; original magnification, × 400) are shown. (C) Growth inhibition of leukemic blast cells by WT1 antisense oligomers. Leukemic blast cells and AML1-ETO-expressing Kasmi-1 cells were treated with WT1 AS or random oligomers, and the numbers of viable cells were counted at 72 hours after the start of treatment. Open and closed columns represent random oligomers and WT1 AS, respectively. The percent growth was defined as the ratio of the number of viable cells treated with WT1 AS or random oligomers to that of cells treated with PBS. ^**P < .005. (D) May-Giemsa-stained BM cells from mice that received a transplant of the splenocytes from the leukemic mice (original magnification, × 1000). (B right, D) Images were visualized and acquired as described in Figure 4B.