Hypothesis: The statistical significance of new staining method using aminoacyl-tRNA synthetases (ARSs) group in normal bile duct cells and the bile duct cancer cells collected by endoscopic retrograde pancreaticoduodenoscopy (ERCP) will be compared to prove the usefulness of the new staining method.~Clinical study design: The bile duct cytology will be obtained by brushing cytology using ERCP in patients with biliary stenosis. The expression of ARSs in the brushing cytology will be evaluated by a new staining method and compare with the results of the conventional cytology staining method including Papanicolaou staining. Immunofluorescence or immunocytochemistry staining will be performed to differentiate the presence of the tumor. The sensitivity and specificity of the new staining method will be compared with the conventional staining method and its usefulness be confirmed.
The sensitivity of brushing cytology used to distinguish the cause of biliary strictures is low and clinical usefulness is not secured. The aim of this study was to validate the clinical usefulness of a new differential staining method for cytology which is difficult to differentiate by the conventional staining method using biliary cancer-related protein expressed only in bile duct cancer.