NUT

Nuclear protein in testis (NUT) is a protein encoded by the NUTM1 gene, mainly existing in the spermatogenic cells after meiosis, which plays a crucial role in the development and maturation of sperm. NUT cancer is a rare poorly differentiated tumor with high invasiveness. The fusion of NUTM1 gene and partner gene is considered as the main pathogenic factor. Among them, NUTM1-BRD4 is the most common. Its expression product can inhibit normal cell differentiation and maintain cancer cell proliferation, leading to poor prognosis for patients. In clinical practice, NUT is the most important diagnostic marker for NUT cancer, and its diffuse (>50%) punctate expression near the nucleus is a crucial feature. In addition, NUT can be used in combination with epithelial biomarkers for differential diagnosis between NUT cancer (+) and poorly differentiated squamous cell carcinoma (-), lymphoepithelioma-like carcinoma (-), mucoepidermoid carcinoma (-), and pleomorphic adenocarcinoma (-).