PITAR silencing in U87 glioma cells increased the luciferase activity from PG13-Luc, a p53-dependent reporter (el-Deiry et al., 1993; Figure 5—figure supplement 1A), decreased PITAR and TRIM28 mRNA levels, and increased CDKN1A mRNA levels with no change in TP53 mRNA levels (Figure 5A). Here, TP53 is linked to central nervous system cancer.