MDM4 and sarcoma: The highest frequencies of short and copy number variants were seen in key regulators of genomic stability such as TP53 (37.1%) and MDM2 (10.7%), and cell cycle regulators including RB1 (17.2%), CDKN2A (16.7%), CDKN2B (12.8%), CDK4 (10.6%), and CDK6 (0.7%) (Fig. 2a, genes with alteration frequencies of ≥1%; Supplementary Fig. S2, genes with observed alteration frequencies of <1% in the total sarcoma cohort and ≥5% in any individual sarcoma).These classes of alterations were also seen in MDM4 (0.5%) and related cell-cycle genes CCNE1 (2.6%), CCND1 (1.0%), CCND2 (1.4%), and CCND3 (1.8%).