In order to rigorously quantify T cells located within the tissue parenchyma, fluorescent T cells were excluded from enumeration in TdLN if they were located within cuboidal high endothelial venules (HEV) that express peripheral lymph node address (PNAd) and are the major portals of naïve T cell entry [21]; transferred T cells were also excluded from quantification if they were within tumor vessels identified by staining for the CD31 pan-endothelial adhesion molecule [22, 24]. This evidence concerns the gene PECAM1 and neoplasm.