In human cancers, ALDH18A1 and PYCR1 are frequently overexpressed and associated with poor survival of patients,3 while depletion of ALDH18A1 or PYCR1 diminishes the proline levels and tumorigenesis.15, 24 In addition, we discover MZF1‐AS1 as an oncogenic lncRNA associated with poor outcome of NB and other types of tumors. Here, ALDH18A1 is linked to cancer.