A study using immunomagnetic enrichment techniques to capture CTCs by utilization of MCAM, MCSP, ABCB5, and CD271 to compare populations of CTCs in circulation between individuals with primary and metastatic melanomas, found that CTC populations were significantly higher in metastatic melanoma (Figure 2A) (Freeman et al., 2012). This evidence concerns the gene ABCB5 and metastatic melanoma.