TP53BP2 and cancer: In addition, the expression of retinoblastoma tumor suppressors RB1 and p53, which are downregulated in CRPC and associated with cancer drug resistance [57], significantly decreased upon JICD overexpression; that is, the expression of RB1 decreased by ~3-fold, and the expression of TP53 downstream target genes decreased as followed: RRM2B and variants by ~5.3-fold, TP53BP2 by ~1.4-fold, and TP53INP1 by ~3.7-fold (Figure 4C).