CD274 and cholangiocarcinoma: To investigate whether integrin αvβ6 and PD-L1 are co-localized within CCA cells, we performed co-localization immunofluorescence staining, revealing a spatial overlap of integrin αvβ6 and PD-L1 expression in KKU-100 and KKU-213A cells, but not in KKU-055 (Fig. 1A, merged images).