PCNA and cancer: This is different from the activity of two small molecule PCNA inhibitors of cancer cell growth that disrupt PCNA during replication, T2AA and PCNA-I1 (Punchihewa et al., 2012; Tan et al., 2012), and rely on the high proliferation rate of these cells (Muller et al., 2013; Choe and Moldovan, 2016).