Notch Intracellular Domain (NICD) Expression and Clinical Manifestations of Second Primary Tumor at Esophagus in Patients with Head and Neck Squamous Cell Carcinoma

Introduction Second primary tumor (SPT) is a major factor that affects the survival of head and neck squamous cell carcinoma (HNSCC) patients, and the esophagus is a common site. Detection of SPT is essential for optimal HNSCC treatment planning and follow-up. Mutation of the NOTCH1 gene is common in head and neck cancer. However, details relating to Notch signaling and clinical outcomes among different primary tumors are still inconclusive. This study aimed to identify the role of the Notch signaling pathway in HNSCC, and to compare NOTCH1 expression in HNSCC compared between those with and without SPT at esophagus while focusing on the Notch intracellular domain (NICD).