Flow cytometry analysis of Annexin V-FITC/Propidium iodide (Pl) staining demonstrated that CP-673451 treatment dose-dependently induced both early-stage apoptosis (Annexin V+/PI−, represented in Quadrant 4 (Q4)) and late-stage apoptosis (Annexin V+/PI+, represented in Q2) in CCA cells, with a significant effect found at concentrations of 5 and 10 μM (Figure 4A). This evidence concerns the gene ANXA5 and cholangiocarcinoma.