부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.mvr.2006.03.005 Byline: Giacomo Azzali Keywords: Lymphatic vessel, tumor cell; Transendothelial passage; Intravasation; Metastatic diffusion; Three-dimensional model Abbreviations: ALV, absorbing lymphatic vessel; TAAL vessel, tumor-associated absorbing lymphatic vessel; TC, tumor cell; LEC, lymphatic endothelial cell; IPT cell, invasive phenotype tumor cell; VEGF, vascular endothelial growth factor. Abstract: The aim of the research is the study of ultrastructural characteristics of the absorbing lymphatic vessel and of tumor cell passage through the endothelial lymphatic wall in (a) subcutaneous xenografts of T84 colon adenocarcinoma and B16 melanoma cell lines in nude mice and (b) human colorectal cancer. It was found that the tumor-associated absorbing lymphatic (TAAL) vessel has the same ultrastructural characteristics as the absorbing lymphatic vessel in normal organs, and it is provided with an endothelial wall wholly lacking a continuous basement membrane, pores, fenestrations, and open junctions. The TAAL vessel is always missing in the studied tumor masses as far as the central stroma is concerned, whereas it is always present in the peripheral area of the tumor and in the peritumoral connective tissue. The factors of extravasal matrix that play an active role in migration process of invasive phenotype tumor (IPT) cell after its detachment from tumor mass, as well as the role of cytoplasmic protrusions (pseudopod-like) in lymphatic recognition, were considered. For the first time, this study demonstrated the transendothelial passage of IPT cell inside the TAAL vessel lumen, which takes place by means of the intraendothelial channel ([approximately equal to] 1.8-2.1 [mu]m in diameter and 6.8-7.2 [mu]m in length). This channel is to be considered a transient morphological entity organized by TAAL vessel endothelium by means of still unidentified molecular mechanisms. Therefore, it appears to be ascertained that the intraendothelial channel represents a step forward in the knowledge of the drainage into lymphatic circulation of interstitial fluid and the answer to the lack of knowledge expressed till today by researchers concerning the modality of passage of the tumor cell through the endothelial wall of the TAAL vessel. Author Affiliation: Lymphatology Laboratory, Section of Human Anatomy, Department of Human Anatomy, Pharmacology and Forensic Medicine, School of Medicine, University of Parma, Via Gramsci, 14 (Ospedale Maggiore), 43100 Parma, Italy Article History: Received 17 November 2005; Revised 6 March 2006; Accepted 20 March 2006