PDZD2 and chronic gastritis: At WGS level, we found a set of nonsynonymous mutation genes occurred in chronic gastritis sample, they are ATXN3, PLIN4, PDZD2, MUC4, MUC17, DMBT1, DAB1, ZNF208, FLG2 and CRNN. It means that somatic gene variations are an accumulative molecular event during early stage of gastric carcinogenesis.