Stem cells give a peak into a possible melanoma breakthrough.
This is actually follow-up research on another breakthrough, the demonstration of a group of receptors, the, yes - ABC family - are key markers for tumor cells. In essence, this can be a unifying tag on the surface of tumor cells that set them apart from the rest of the normal, noncancerous cells in the body. Based on that tag, a therapy might be developed that could use that tag as a target. As mentioned, there are considerations; this receptor, ABCB5, does indeed have a function elsewhere in the body. This is the classic example of what the drug industry likes to call 'side effects'.
Of course, the rub is that melanoma is largely a self-inflicted form of cancer, with the vast majority of cases arising from sun exposure. Might want to make your hat for next summer bigger and floppier, neh?