PYCR1 and neuroblastoma: MZF1‐AS1 facilitates the interaction of PARP1 with E2F1, resulting in upregulation of downstream target genes associated with tumor progression (Figure 8D), such as MZF1,25c‐Kit,26PRKCG,27 and RET. 28 As downstream genes of MZF1, ALDH18A1, and PYCR1 exert important functions in MZF1‐AS1‐mediated proline synthesis, while proline itself may play a determinative role in the aggressiveness of NB cells.