In tumor microenvironment, CSCs have a much higher efficiency of iron absorption than non-CSCs, with an increased expression level of Tf and TfR1, indicating that Tf and TfR1 are essential for the survival of CSCs, and emphasizing the critical importance of iron within these subgroups (Schonberg et al., 2015; Hamaï et al., 2017). Here, TF is linked to neoplasm.