(A) Schematic diagram showing the injection of nanocarbon particles into the subserous layer of the stomach at multiple sites. (B–D) Perigastric lymphatic drainage network. LGA/V, left gastric artery/vein; smaLN, lymph node along the superior mesenteric artery. Scale bars: 5 mm. (E) Schematic diagram of orthotopic xenograft tumor model. A small piece of tumor tissue was implanted to the submucosal layer by an implantation needle. (F) Bioluminescence imaging was used to track tumor growth. (G) MR imaging was used to track tumor growth and lymphatic metastasis. Scale bar: 5 mm. (H) Statistics analysis on the size of lymph nodes in MR imaging (n = 4). (I) Gross images of the stomach and perigastric drainage lymph node of mice, and statistics analysis of the volume of lymph nodes (n = 4). (J) H&E and pan-cytokeratin (CK-pan) staining of stomach and perigastric lymph nodes. LVI, lymphovascular invasion. The magnification of representative images of gcLN, lcLN, caLNs and paLN were the same. (K) Schematic diagram showing the broad application of this orthotopic gastric cancer mouse model. LNM, lymph node metastasis. The arrows (B, G, I, and J) indicate the position of lymph nodes. Multiple unpaired 2-tailed t test was performed for statistical analysis. *P < 0.05 and ****P < 0.0001. Data represent mean ± SEM.