In summary, these results strongly indicate that CD44+ cells have a limited proliferation ratio in vehicle-treated cells but, conversely, the recurrent tumor develops mainly from CD44+ cells, since they show a high proliferative index, coupled with a loss of the epithelial to mesenchymal transition (EMT) marker ZEB1, and an increased expression of the differentiation associated protein MUC1. Here, MUC1 is linked to neoplasm.