In this report, we demonstrate increased expression of glycolytic and mitochondrial markers within CLL PCs, with a concomitant increase in the metabolic activity of the CXCR4lowCD5high fraction of peripheral blood CLL cells that have recently egressed from the lymph node.15 We show that anti-IgM stimulation of CLL cells causes them to adopt many features of the “Warburg effect,” including increased glucose uptake, increased lactate production, and induction of glycolytic enzyme expression. The gene discussed is HK1; the disease is B-cell chronic lymphocytic leukemia.