We previously reported that Pin1 is overexpressed and closely correlated with Rb phosphorylation in DMBA-induced tumors in mice, compared with normal mammary glands.53 Also, Pin1 expression correlates with Rb phosphorylation in human glioma samples,54 suggesting that increased Pin1 expression could account, at least in part, for Rb inactivation. Here, PIN1 is linked to glioma.