PIN1 and cancer: The current understanding stems primarily from observations that Pin1 is overexpressed/has increased activity in most cancers and cancer stem cells, with corresponding negative prognostic outcomes (Ayala et al., 2003; He et al., 2007; Tan et al., 2010; Girardini et al., 2011; Luo et al., 2014; Rustighi et al., 2014; Xu et al., 2016; Nakatsu et al., 2019).