CDKN2A and fibrosarcoma: In addition, we observed an increased incidence of histiocytic sarcoma (31.0% vs 15.4%, P = 0.042) and soft tissue sarcomas, excluding fibrosarcomas (5.9% vs 0%, P = 0.0487) in hTS/Ink4a/Arf−/− as compared to control Ink4a/Arf−/− mice (Table 2).