Histopathological analysis of representative UVR-induced primary and metastatic melanomas of all three strains revealed (Fig. 1d) characteristics identical to those previously described for HGF mice with wild-type or hemizygous-null genotypes at the Nme1:Nme2 locus.6 All melanoma specimens harboured varying ratios of both epithelioid and dendritic melanoma cells that were highly pigmented (Supplementary Table 2). This evidence concerns the gene NME2 and melanoma.