In the consultation of gastric neuroendocrine tumors, many patients and families tend to confuse G1, G2, and G3 with type 1, type 2, and type 3. Now let’s talk about the difference and connection of these basic concepts, grading and staging. According to the degree of tumor differentiation, the level of serum gastrin and gastric acid secretion, patients with gastric neuroendocrine tumors are classified into 4 types, i.e., type 1, type 2, type 3 and type 4. Different typing results in different clinical characteristics, treatment strategies and prognosis. And G1, G2 and G3 refer to the grading of the tumor; the higher the grading, the greater the malignancy. The pathological grading of gastroenteropancreatic neuroendocrine tumors can be divided into G1 (grade 1), G2 (grade 2) and G3 (grade 3). These G1G2 or G3 (grading of the tumor) are determined by the pathologist, under the microscope, by observing the pathological sections (HE staining and immunohistochemical Ki-67 index) in a comprehensive manner, and the grading of the tumor will appear in the pathology report. The clinical classification of gastric neuroendocrine tumors is based on gastroscopy, serum gastrin, gastric acid secretion, clinical symptoms, and pathological grading, etc. Patients with type 1 have the best prognosis, with elevated gastrin and gastric pH monitoring suggesting gastric acid deficiency. Patients with type 1 have the best prognosis, with elevated serum gastrin and gastric pH monitoring suggesting gastric acid deficiency, with pathology of NET G1 and a few of NET G2; patients with type 2 have a better prognosis, with markedly elevated serum gastrin and more gastric acid, with heartburn, acid reflux and stomach pain, requiring long-term acid-suppressing drugs, and pathology of NET G1 or NET G2; patients with type 3 have normal serum gastrin and normal gastric acid secretion, with pathology of NET G1, NET G2, or NET G3. The prognosis is the worst. Therefore, in gastric neuroendocrine tumors, grading and staging are both different and related, G1 is not equal to type 1, G2 is not equal to type 2, and G3 is not type 3. Don’t confuse pathological grading with clinical staging.