Given that cell cycle progression was induced in every human T-ALL cell line cultured in ACM, and our gene expression profiles demonstrating adipocyte-induced alterations in CHEK1 and CHEK2 levels in malignant T cells, we next determined total and activated CHEK1 and CHEK2 protein levels in leukemia cells cultured under each condition. The gene discussed is CHEK1; the disease is acute lymphoblastic leukemia.