Research suggests that tumor-derived Periostin (POSTN) and ITGB3 are key components in maintaining breast cancer stem cells (BCSCs), but there is significant variability in their ability to initiate mammosphere growth, with only MIII cells expressing high surface levels of αvβ3 forming stable mammospheres (Lambert et al., 2016). The gene discussed is POSTN; the disease is breast carcinoma.