PIN1 and cancer: Since aberrant accumulation of β-catenin contributes to abnormal development and tumorigenesis, Pin1 regulates many processes in development and tumor formation, including osteoblast and neuronal differentiation, cancer cell proliferation, and drug resistance, via affecting the transcriptional activity of β-catenin (Ryo et al., 2001; Nakamura et al., 2012; Shin et al., 2016; Wang et al., 2016).