Notch family proteins have been reported to be associated with the initiation and development of various types of tumors. The present study used a prospective design to investigate the role of Notch proteins as novel biomarkers that are capable of predicting the survival outcome for patients with non-small cell lung cancer (NSCLC). The protein expression of Notch 1, Notch 3 and their ligands, Jagged 1 and Delta-like 4, was examined using immunohistochemistry in NSCLC tissues and adjacent non-cancerous lung tissues from 101 patients who underwent surgical treatment. The expression was also correlated with clinicopathological parameters and overall survival (OS). High Notch 1 protein expression was observed in 55.4% (56/101) of NSCLC samples and high Notch 3 expression was observed in 53.5% (54/101). The nuclear expression of Notch 3 was significantly associated with the lymph node status (P=0.0026) and tumor-node-metastasis (TNM) stage (P<0.0001), while the coexpression of Notch 1 plus Notch 3 was associated with lymph node status (P=0.0056), TNM stage (P=0.0001) and the histological grading (P=0.0359). In the survival analyses, the high expression of Notch 1 and Notch 3 exhibited an additive effect toward a poorer OS compared with a subtype with low coexpression for the two proteins (P<0.001), with high nuclear Notch 3 expression in the NSCLC patients maintaining independent prognostic significance for the outcome on multivariate analysis. These data further demonstrate a central role for Notch signaling in NSCLC and the significance of Notch 3 as a prognostic indicator of a poorer survival for patients with resected NSCLC.
Keywords: Notch 1; Notch 3; immunohistochemistry; non-small cell lung cancer; prognosis.