Taken together, these results seem to suggest that (i) leukemic cells display a high degree of heterogeneity in their metabolism; (ii) those which turn out to be resistant to therapeutic agents are generally characterized by a highly active metabolism; (iii) mTOR is the master regulator of leukemic cell metabolism, but we are only beginning to understand the mechanisms by which it operates in the leukemia cell setting. The gene discussed is MTOR; the disease is leukemia.