The very high rate of induction of histiocytic sarcoma observed using p16p19−/−; Kras(G12V) BM cells as a donor cell population prompted us to ask whether this might be an intrinsic property of this oncogenic combination, or whether histiocytic sarcomas can be introduced in NOD.SCID mice using other leukemogenic systems. Here, KRAS is linked to histiocytic sarcoma.