ABCG2 and metastatic melanoma: A novel human ABC transporter, ABCB5 (ATP-binding cassette, sub-family B (MDR/TAP), member 5), has been reported to be expressed significantly more in primary and metastatic melanoma than in benign melanocytic nevi; moreover, the expression of ABCB5 is higher in metastatic melanomas than in primary lesions [12,13].