In the therapeutic setting, major applications of administration of recombinant (r) G-CSF include: (i) attenuation of the magnitude and duration of chemotherapy-induced neutropenia in cancer patients [2], described in greater detail below; (ii) treatment of cyclic and chronic neutropenias [3,4]; and (iii) mobilization of hematopoietic progenitor cells into peripheral blood to be harvested for stem cell transplantation. This evidence concerns the gene CSF3 and cancer.