p21Cip1/Waf1 has been observed to be overexpressed consistently in several types of liver disease (Aravinthan et al., 2013a; Aravinthan et al., 2013b) and cholangiopathies (Ferreira-Gonzalez et al., 2018) and inhibits the activity of cyclin-dependent kinases (CDKs). The gene discussed is CDKN1A; the disease is liver disorder.