CDKN2A and undifferentiated (embryonal) sarcoma: Some researchers further analyzed the three proteins above and found that MDM2+/p16+ were all WDL, MDM2-/p16- was benign fatty tumor, MDM2/CDK4/p16 was DDL, and MDM2-/CDK4-/p16- was a kind of undifferentiated sarcoma.