There is currently no general consensus regarding safe use of granulocyte colony stimulating factor and thrombopoietin-receptor agonists and, in general, for cytopenias lasting more than a month, marrow examination is recommended, as this can rule out involvement with the primary malignancy or with myelodysplastic syndrome/acute myelogenous leukemia as a cause of cytopenias [43]. The gene discussed is MPL; the disease is myelodysplastic syndrome.