In addition, it was recently demonstrated that tumour cells in the CSF attain phenotypic changes to allow them to out-compete other cells for iron, by upregulating expression of the iron-binding protein lipocalin-2 (LCN2) and its receptor SLC22A17, which was subsequently shown to promote cancer cell growth in the leptomeningeal space (Figure 3B) [110]. Here, LCN2 is linked to cancer.