Expressions of Notch signaling-associated proteins in esophageal squamous cell carcinoma

Objective: To investigate the expressions and the role of Notch signaling-associated proteins in esophageal squamous cell carcinoma (ESCC).

Methods: Fifty patients with ESCC were included in this study. The expressions of Notch signaling-associated protein (4 receptors: Notch1, Notch2, Notch3, Notch4; 5 ligands: Dll1, Dll3, Dll4, Jagged1, Jagged2) in cancer foci and adjacent normal tissues (5 cm distance to cancer) were examined by immunohistochemitry. Correlations of these proteins with cancer cell proliferation(Ki-67 index) and clinicopathologic features were investigated.

Results: Higher levels of Notch1 and Notch2 were measured in cancer foci compared with adjacent tissues (all P<0.05). There were no differences in the expressions of Notch3, Dll1 and Dll3 (all P>0.05). Notch4, Dll4 and Jagged2 were not detected in both cancer foci and adjacent tissues. Notch1 expression was negatively correlated with lymph node metastasis and TNM staging (all P<0.01). Jagged 1 expression was positively correlated with TNM staging (P<0.01). Ki-67 index was obviously higher in cancer foci, while it was negatively correlated with Notch1 and Notch3 (all P<0.01) and positively correlated with Dll1 and Jagged 1 (all P<0.01).

Conclusions: Notch signaling path may act as tumor suppressive gene in the pathogenesis of esophageal squamous cell cancer, in which Notch1 protein plays an important role.