title: Evidence for an additional metastatic route: in vivo imaging of cancer cells in the primo-vascular system around tumors and organs.
abstract: OBJECTIVE
  Researchers have been studying the mechanisms by which metastasis can be prevented via blocking the hematogenous and the lymphatic routes for a long time now. However, metastasis is still the single most challenging obstacle for successful cancer management. In a new twist that may require some retooling of this established approach, we investigated the hypothesis that tumor metastases can occur via an independent fluid-conducting system called the primo-vascular system.
  
  
  METHODS
  The dissemination and growth of near-infrared quantum dot (NIR QD)-electroporated cancer cells in metastatic sites were investigated using in vivo multispectral imaging techniques.
  
  
  RESULTS
  Our results show that the NIR QD-labeled cancer cells were able to migrate through not only the blood vascular and lymphatic systems but also the primo-vascular system extending from around the tumor to inside the abdominal cavity. Furthermore, the NIR QD-labeled cancer cells, which had been seeded intraperitoneally, specifically infiltrated the primo-vascular system in the omentum and in the gonadal fat.
  
  
  CONCLUSIONS
  These findings strongly suggest that the primo-vascular system may be an additional metastasis route, complementing the lymphatic and hematogenous routes, which facilitate the dissemination and colonization of cancer cells at secondary sites.
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Yoo
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
authors.forename: Hong Bae
authors.initials: HB
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
authors.forename: Nayoun
authors.initials: N
authors.lastname: Won
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
authors.forename: Jiwon
authors.initials: J
authors.lastname: Bang
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
authors.forename: Sungjee
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
authors.forename: Saeyoung
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
authors.forename: Byung-Cheon
authors.initials: BC
authors.lastname: Lee
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul, South Korea. kssoh1@gmail.com.
authors.forename: Kwang-Sup
authors.initials: KS
authors.lastname: Soh
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D003952:Diagnostic Imaging / Q000379:methods*; D004195:Disease Models, Animal; D018274:Electroporation; D005260:Female; D006066:Gonads / Q000473:pathology; D006801:Humans; D042601:Lymphatic Vessels / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000098:blood supply* / Q000473:pathology*; D009852:Omentum / Q000473:pathology; D009928:Organ Specificity; D010051:Ovarian Neoplasms / Q000473:pathology; D045663:Quantum Dots; D040521:Subcutaneous Tissue / Q000473:pathology; D014410:Tumor Stem Cell Assay; D023041:Xenograft Model Antitumor Assays