title: The Significance of p53 and K-ras Immunocytochemical Staining in the Diagnosis of Malignant Biliary Obstruction by Brush Cytology during ERCP.
abstract: OBJECTIVE
  Brush cytology during ERCP can provide a pathologic diagnosis in malignant biliary obstruction. K-ras and p53 mutations are commonly found in biliary and pancreatic cancers. We evaluated the diagnostic yield of brush cytology and the changes obtained by adding p53 and K-ras staining.
  
  
  METHODS
  One hundred and forty patients with biliary obstruction who underwent ERCP with brush cytology during a 7-year period were included. The sensitivity and specificity of brush cytology only and with the addition of p53 and K-ras staining were obtained.
  
  
  RESULTS
  Malignant biliary obstruction was confirmed in 119 patients. The sensitivity and specificity of brush cytology were 78.2% and 90.5%, respectively. The sensitivity of cytology was 77.3% at the ampulla-distal common bile duct (CBD), 92.6% at the mid common hepatic duct (CHD), and 94.7% at the proximal CBD-CHD (p<0.05); these values did not differ with the degree or the length of the obstruction. In the 97 patients who received additional p53 and K-ras staining, the sensitivity of cytology plus p53 was 88.2%, cytology plus K-ras was 84.0%, and cytology plus p53 and K-ras was 88.2%. The sensitivity of cytology plus p53 was higher than that of brush cytology only (95% confidence interval: 83.69-92.78 vs 72.65-83.65) but not that of cytology plus K-ras.
  
  
  CONCLUSIONS
  Brush cytology for malignant biliary obstruction has a high diagnostic accuracy. Adding p53 staining can further improve the diagnostic yield, whereas K-ras staining does not.
authors.affiliation: Department of Internal Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
authors.forename: Young Sup
authors.initials: YS
authors.lastname: Kim
authors.forename: Ho Gak
authors.initials: HG
authors.lastname: Kim
authors.forename: Jimin
authors.initials: J
authors.lastname: Han
authors.forename: Change Jae
authors.initials: CJ
authors.lastname: Hur
authors.forename: Byeong Suk
authors.initials: BS
authors.lastname: Kim
authors.forename: Jin Tae
authors.initials: JT
authors.lastname: Jung
authors.forename: Joong Goo
authors.initials: JG
authors.lastname: Kwon
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.forename: Chang-Ho
authors.initials: CH
authors.lastname: Cho
authors.forename: Yoon Kyung
authors.initials: YK
authors.lastname: Sohn