Low CXCL12 expression in human primary cutaneous melanomas has been associated with poor prognosis102 and shown to be predictive of metastasis103, and CXCL12 is one of 789 genes displaying reduced expression in ‘high grade’ human primary cutaneous melanomas that is a member of a 1,864 gene expression signature that delineates two classes of primary cutaneous melanomas with significantly different rates of metastasis104. Here, CXCL12 is linked to cutaneous melanoma.