Heavily pigmented metastases were obtained in a melanoma mouse model with the genetically mediated stabilization of β-catenin [41], and we found that several genes involved in differentiation that were up-regulated in that model (e.g., TYR, TYRP1, DCT, SLC45A, SLC24A, RAB27A) were also highly expressed in melanospheres. Here, TYRP1 is linked to melanoma.