E2F1 and neuroblastoma: Moreover, knockdown or overexpression of PARP1 and E2F1 abolished the increased and decreased 13C glutamine‐to‐proline conversion, proline levels, protein synthesis, anchorage‐independent growth, and invasion of NB cells induced by stable ectopic expression or silencing of MZF1‐AS1 (Figure 6E–G; Figure S8A, Supporting Information).