Moderately differentiated adenocarcinoma of gastric cancer is one of the histopathologic types, and gastric cancer can be classified into five major types according to the histologic type: adenocarcinoma, adenosquamous carcinoma, squamous cell carcinoma, undifferentiated carcinoma and undifferentiated carcinoma. Among them, adenocarcinoma is the most common pathological type, and adenocarcinoma includes papillary adenocarcinoma, tubular adenocarcinoma, mucinous adenocarcinoma, and indolent cell carcinoma. Adenocarcinoma is further classified into three major categories: highly differentiated adenocarcinoma, moderately differentiated adenocarcinoma, and poorly differentiated adenocarcinoma according to the degree of differentiation of tumor cells. Among them, highly differentiated adenocarcinoma has the smallest difference between tumor cells and normal cells, so its prognosis is better; lowly differentiated adenocarcinoma has a larger difference between tumor cells and normal cells, and its prognosis is the worst, and moderately differentiated adenocarcinoma is in between.