The connecting segment 1 (CS-1) is a cell attachment domain located in the type III homology connecting segment (IIICS) of fibronectin. CS1 peptide of fibronectin, which lacks the Arg-Gly-Asp-containing domain, actively inhibits tumor metastases in spontaneous and experimental metastasis models. The use of Fibronectin CS1 Peptide might offer a promising therapeutic approach for combating and preventing cancer metastasis.