The present invention is directed to methods of detecting viable epithelial cells in a sample. The method includes isolating the sample comprising cells from a patient and culturing the cells for a time sufficient for an epithelial cell-specific marker to be released from the cells. The marker includes a substantially full-length cytokeratin. The method further includes detecting the released marker. Detection of the marker indicates the presence of disseminated epithelial cells. Methods are also directed to identifying disseminated epithelial tumor cells.