During the metastatic cascade, the mesenchymal CD44+CD24− phenotype is crucial for the initial steps, as it is important for cells to be able to enter the circulation, as well as to seed and form micrometastasis; however, when the invasive edge becomes the interior of the tumour, the switch to the ALDH+ epithelial state is important for establishing macrometastasis. This evidence concerns the gene CD44 and neoplasm.