Consequently, TFK-1 cell proliferating ability decreased by HDAC1 silencing was partially rescued by overexpression of TPX2 as revealed from trypan blue staining and colony formation assays (Fig. 4D, E), suggesting that silence of HDAC1 downregulated TPX2 expression to suppress CC proliferation in vitro. The gene discussed is HDAC1; the disease is cholangiocarcinoma.