KIDINS220 and neoplasm: We initially measured circ-ZNF609 expression in wild-type (WT) myoblasts versus RMS cell lines (RD and RH4 cells, two in vitro models of ERMS and ARMS subtypes, respectively) and found a consistent upregulation of the circRNA in both the tumor cell lines, with particularly higher levels in the alveolar type (Fig. 2a).