Fig. 1

Lymph nodes were dyed with carbon nanoparticles injected into the upper esophagus. A Carbon nanoparticle suspension was injected into the submucosa of upper thoracic esophagus. B The injection site was shown. C The left gastric lymph nodes were labeled with the carbon nanoparticles. D A left gastric lymph node was labeled by the nanoparticles. E A celiac lymph node was not labeled. F The subcarinal lymph node was black-dyed before injection of carbon nanoparticles. G The left gastric lymph node was labeled by the carbon nanoparticles (H–E × 40). H The celiac lymph node was not labeled. I Deposition of black substances (arrow) was shown in the subcarinal lymph node (H–E × 40) before injection of the nanoparticles