Mathematical modeling suggests that the magnitude of the effect of G-CSF could differ with respect to the grade of neutropenia 300–500/mm3, 50–300/mm3, and less than 50/mm3 upon the dose of G-CSF, which are considered standard for short-acting at five microgram/kg or long-acting at 100 microgram/kg in the subcutaneous or continuous intravenous administration of 10 microgram/kg/day [24]. This evidence concerns the gene CSF3 and neutropenia.