Interestingly, studies which have used the expression of keratin KRT19 as a measure of the metastatic potential of different cancer cell lines have found that it is overexpressed in breast cancer cells, such as MCF-7 and MDA-MB-231 cells in comparison with other cancer cell types and is very low specifically in SH-SY5Y cells39, indicating lower metastatic capabilities in the neuroblastoma cell line, and therefore, more of an affinity to static cellular microenvironments like the primary fibroblasts (see ‘Tumour Cells’ in Fig. 1). Here, KRT19 is linked to breast cancer.