ACTB and cholangiocarcinoma: Peptides with differential excretion levels in bile of patients with CCA compared to those with benign strictures, were fragments from the hemoglobin subunits α (HBA1) and β (HBB), the inter-α trypsin inhibitor heavy chains H2 (ITIH2) and H4 (ITIH4), cytoplasmic actin 1 (ACTB) and serum albumin (ALB).