A Single-Center Follow-Up Study of Low-Grade Gastric Intraepithelial Neoplasia and the Screening of Key Genes of Precancerous Lesions oleh Xiao-Xu Jin, Xiao-Li Xie, Fu Niu, Kai-Ge Yin, Chen-Guang Ji, Jin-Feng Cui, Li Liu, Zhi-Jie Feng