IRS scores for the p-ATM expression in the normal nevi were in between 1 & 8 with none of the cores achieving a score of either 0 or 9 to 12, whereas, 12.5% cases of dysplastic nevi samples were scored as ‘negative’ (0) and 6.25% of cases received an IRS score of 9 to 12. This evidence concerns the gene ATM and dysplastic nevus.