For a molecular insight in Notch3-boosted CXCR4 expression, we modulated Notch3 function in a human leukemia cell-line, TALL-1 cells, characterized by CD4/CD8/CD3 expression, Notch3 activating mutations without known alterations of Notch1 [4], and here, for the first time, by high CXCR4 cell-surface expression (Fig. 7a). The gene discussed is CD4; the disease is leukemia.