In GEP–NENs, immunohistochemical staining for PD-L1 has shown expression in approximately 20% of cases.[10] Compared with low-grade neuroendocrine tumors, there is an increased expression of PD-L1 in high-grade (G3) and poorly differentiated neuroendocrine carcinomas, which correlates with a poorer prognosis,[11] PD-1/PD-L1 immunotherapy may be efficacious in high-grade GEP–NENs. The gene discussed is CD274; the disease is neuroendocrine neoplasm.