A recombinant polynucleotide encoding migrating stimulating factor (MSF) or variants or fragments or derivatives or fusions thereof or fusions of said variants or fragments or derivatives. Reagents are disclosed which can distinguish MSF and fibronectin, and which can distinguish polynucleotides which encode MSF or fibronectin. These reagents are believed to be useful in, for example, diagnosing cancer. MSF or variants or fragments or derivatives or fusions thereof, or fusions of said variants or fusions or derivatives, are useful in modulating cell migration and in wound healing.