RB1 and neoplasm: Molecular analyses using WES [9–14], targeted panel sequencing [15–17] and limited WGS [11, 14] have revealed the most commonly altered genes in uLMS to be TP53 followed by RB1, ATRX, PTEN and MED12. WGS revealed that a high proportion of tumours (76%) harbour chromothripsis/chromoplexy [14].