To determine the expression levels of JAG1 and miR‐124 in gastric carcinoma, we selected eight pairs of GC tissues and matched normal tissues adjacent to the tumour, and one normal gastric cell line GES‐1 and four malignant human GC cell lines (SGC‐7901, MGC‐803, BGC‐823 and KATO‐3). The gene discussed is JAG1; the disease is neoplasm.