ITGB4 and cholangiocarcinoma: To validate the potential involvement of ITGB4 in regulating gemcitabine sensitivity in cholangiocarcinoma cells, qRT-PCR analysis was first performed, revealing that transfection with ITGB4-targeting siRNA significantly reduced ITGB4 mRNA expression in both HUCCT1 and RBE cells (Figure 7A).