Interestingly, of the 26 hTS/Ink4a/Arf−/− mice that developed histiocytic sarcoma, 22 (85%) showed tumor infiltration in multiple tissues ranging from 4 to 9 organs (Table 1) compared to Ink4a/Arf−/− mice where histiocytic sarcoma predominantly localized to lymph nodes and spleen (Table 1). The gene discussed is CDKN2A; the disease is neoplasm.