• Takashi Sugino, Tomiko Yamaguchi, Go Ogura, Atsuko Saito, Takeaki Hashimoto, Nobuo Hoshi, Sayaka Yoshida, Steve Goodison, and Toshimitsu Suzuki.
• Department of Pathology, Fukushima Medical University School of Medicine, Fukushima, 960-1295, Japan. sugino@fmu.ac.jp
• Bmc Med. 2004 Apr 5; 2: 9.

BackgroundWe have previously described an alternative invasion-independent pathway of cancer metastasis in a murine mammary tumor model. This pathway is initiated by intravasation of tumor nests enveloped by endothelial cells of sinusoidal vasculature within the tumor. In this study, we examined whether evidence for the invasion-independent pathway of metastasis is present in human cancers.MethodsArchival specimens of 10 common types of human cancers were examined for the presence of sinusoidal vasculature enveloping tumor nests and subsequently generated endothelial-covered tumor emboli in efferent veins.ResultsA percentage of tumor emboli in all cancers was found to be enveloped by endothelial cells, but these structures were particularly prevalent in renal cell carcinomas, hepatocellular carcinomas and follicular thyroid carcinomas. A common feature of the vasculature in these tumors was the presence of dilated sinusoid-like structures surrounding tumor nests. A high mean vascular area within tumors, an indication of sinusoidal vascular development, was significantly related to the presence of endothelial-covered tumor emboli.ConclusionsThese results suggest that an invasion-independent metastatic pathway is possible in a wide variety of human cancers. Further investigation of this phenomenon may present new therapeutic strategies for the amelioration of cancer metastasis.

11 keywords...

hide…