MYC and cholangiocarcinoma: Xu L. et al., [43] observed that the histone deacetylase sirtuin 2 (SIRT2) and its downstream target cMYC, were overexpressed both in two human CCA cell lines (HUCCT1 and RBE) with respect to normal bile duct epithelial cells and in 48 CCA samples compared to adjacent tissues.