Hence, we surmised that C12 mediated NOD1 activation must be involved in circulating tumor cell (CTC) interaction with the ECM, especially, collagens and fibronectins, which are found in abundance in various organs and structures, including the subendothelial layers of blood vessels and basement membranes of various tissues (Kramer et al., 1980; Liu et al., 1990; Whelan and Senger, 2003). This evidence concerns the gene FN1 and neoplasm.