It is noted that dense immune response is visible at the periphery of the microsatellite in panel D. We studied a larger group of 12 cases by immunohistochemistry and showed PAEP protein overexpression in microsatellites in five of 12 cases. Intriguingly, screening of additional cases with the PAEP immunostain also identified a histologically inapparent sub-clone within a primary melanoma that shares PAEP expression with the microsatellite and could therefore represent the sub-clone of origin for the microsatellite (Fig. 6). Here, PAEP is linked to melanoma.