Evidence for an additional metastatic route: in vivo imaging of cancer cells in the primo-vascular system around tumors and organs.
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.
Yoo
Jung Sun
JS
Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
Kim
Hong Bae
HB
Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
Won
Nayoun
N
Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
Bang
Jiwon
J
Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
Kim
Sungjee
S
Department of Chemistry, Pohang University of Science and Technology, Kyungbuk, South Korea.
Ahn
Saeyoung
S
Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
Lee
Byung-Cheon
BC
Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
Soh
Kwang-Sup
KS
Department of Physics and Astronomy, Seoul National University, Seoul, South Korea. kssoh1@gmail.com.
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