The present invention relates generally to the fields of treatment, prophylaxis and diagnosis of cell-based and fibrotic conditions in animals including mammals. More particularly, the present invention contemplates the use of agents which modulate epithelial-mesenchymal transition (EMT) processes and mesenchymal-epithelial transition (MET) processes and hence are useful in the treatment of a range of conditions including inhibiting metastasis of solid tumors and the development of fibrosis, treating metastatic disease and in promoting wound healing. Diagnostic protocols to assess EMT and MET or its stage of development also form part of the present invention. The EMT and MET modulating agents are also useful in regulating gene expression and, hence, represent useful therapeutic and research tools.