PRODH and glioma: The upregulation of POX expression at both mRNA and protein levels was not observed in U251 cells, a human glioma cell line that harbors a mutated form of p53 (R273H) (Figure 2A), or H1299 cells, a human lung carcinoma cell line that lacks p53 (Supplementary Figure S2D; Giaccone et al., 1992).