Plasminogen (92–94 kDa) is secreted by the liver as a single-chain glycosylated protein and has been shown to bind to a broad range of eukaryotic cells such as fibroblasts [73], endothelial cells [74], keratinocytes [75], and circulating blood cells including monocytes [76], macrophages [77] and platelets [78], as well as human cancer cells of various types (reviewed by Ranson and Andronicos 2003 [79]). This evidence concerns the gene PLG and cancer.