In recent years, advances in endoscopic ultrasonography–guided fine needle aspiration (EUS-FNA) have played a role in improved preoperative diagnosis, including tumor differentiation and the WHO grade (Ki-67 index).25 The diagnostic accuracy of EUS-FNA in evaluating the WHO grading has been reported as 75% to 83%,26,27,28 with higher accuracy in smaller tumors due to low tumor heterogeneity.29,30 Therefore, we can reliably identify low-grade NF-PanNETs preoperatively and make treatment plans based on their Ki-67 index. The gene discussed is MKI67; the disease is neoplasm.