Fig. 5. Two representative cases showing the estimated evolutionary history of lymph node metastasis in gastric cancer considering their anatomical locations based on the inferred phylogenies and migration history.

a In patient GCM10, the primary tumor was located in the mid-body of the stomach and there was metastasis to multiple lymph nodes (LNs) including para-aortic LN (#16), a distant LN, and the liver. b In patient GCM11, the primary tumor was located in the upper body of the stomach and metastasis for multiple LNs was observed, including in superior mesenteric vein (#14v) and for para-aortic LN (#16); both were regarded as distant LNs. In both cases, the inferred migration history of the LN metastasis was polyclonal parallel single source seeding, indicating that each LN metastasis was from the primary tumor directly rather than sequential metastasis between the proximal to distal tumors. P primary tumor, LN lymph node, Li liver metastasis, E expired.