SERPINB3 and cholangiocarcinoma: Regarding the low percentage of patients positive for SerpinB3/4 in tissue and in the serum, these results are in line with the percentage of well-known prognostic molecular alterations recently studied in a real-world cohort of patients with biliary tract cancer [53], although the recently described analysis of a proteomic profile of circulating extracellular vesicles could open new scenarios and improve the identification of patients at risk of CCA development [54].