A method of detecting a cancer stem cell or circulating tumor cell that has undergone epithelial-mesenchymal transition, comprising determining the level of caveolin-1 expressed by a sample cell, and comparing the level of caveolin-1 expressed by the sample cell to a control, wherein higher expression of caveolin-1 by the sample cell indicates that the sample cell is a cancer cell, as well as a method of detecting cancer or metastasis in a subject, and related methods and compositions.
