MYCN and neuroblastoma: Knockdown of circARID1A in four different neuroblastoma cell lines, two MYCN-amplified (IMR-5, LS) and two non MYCN-amplified (SH-EP, SH-SY5Y) by two independent siRNAs directed against the back-splice junction strongly reduced circARID1A levels in comparison to a scrambled control siRNA with no significant change in ARID1A mRNA levels (Fig. 5d, e).