Notch signaling has been reported to be activated to promote biliary epithelial cell differentiation and tubulogenesis during bile duct development. In this study, clinicopathological significance of aberrant expression of Notch receptors in intrahepatic cholangiocarcinoma (ICC) was investigated. Thus, forty-one ICC specimens were examined by immunohistochemistry using anti-Notch1-4 antibodies, respectively. Expression of Notch receptors was scored by percentage of positive tumor cells and intensity of immunostaining. Clinicopathological parameters and survival data were compared with the expression of Notch receptors, respectively. Expression of Notch receptors was identified in cancer cells, as well as in non-neoplastic cells. Compared with adjacent non-tumor liver tissues, Notch1 and 4 were up regulated, and Notch2 and 3 were relatively weaker. Positive immunostaining of Notch1 in ICC cells was detected in 34 cases (82.9%), Notch2 in 23 (56.1%), Notch3 in 16 (39.0%) and Notch4 in 14 (34.1%). Notch1 was overexpressed in cases with tumor size > 5 cm (P = 0.036). Expression of Notch2 was correlated inversely with histological grade (P = 0.016). Overexpression of Notch4 was more common in cases with serum CA125 > 35 U/ml than cases with CA125 ≤ 35 U/ml (P = 0.048). Expression of Notch3 was not correlated with any other clinicopathological parameters. Moreover, Notch4 was related to poor survival (P < 0.001). To conclude, this study reveals that aberrant expression of Notch receptors 1 and 4 might play important roles during ICC progression.
Keywords: Intrahepatic cholangiocarcinoma; Notch receptors; immunohistochemistry.