Overexpression of CypA in CCA tissue specimens. Immunohistochemistry of CypA expression in cancerous and cancer-adjacent normal bile duct was examined. (A) CypA immunostaining in one representative paired CCA case. Stronger staining for CypA (dark brown) is seen in tumor tissue compared with adjacent normal bile duct lining cells (arrows). (B) CypA immunoreactivity index in normal bile duct versus CCA for 57 paired CCA cases. The majority of the paired tissue specimens (39/57, 68%) demonstrated higher CypA expression in malignant areas than in adjacent normal bile duct areas. (C) The overall median of the CypA immunoreactivity index is significantly higher in CCA samples compared to the adjacent normal bile duct tissue (P < 0.05; n = 57).