Of the 6 RGS-treated animals that eventually succumbed to a lethal myeloproliferative disorder, 5 simultaneously developed T-cell acute lymphoblastic leukemia (T-ALL)/ thymic lymphoma with a predominance of CD4+CD8+ and CD8+ cells (data not shown) [17, 18]. The gene discussed is CD8A; the disease is T-cell acute lymphoblastic leukemia.