In a retrospective study comparing 14 cases of benign subungual melanocytic proliferation with 13 cases of NUM in situ, 92.9% of patients with benign melanonychia showed completely negative staining for Preferentially Expressed Antigen in Melanoma (PRAME) while 76.9% of patients with NUM in situ exhibited >50% immunostaining for PRAME [42]. This evidence concerns the gene PRAME and melanoma.