TERT positivity as a test for melanoma versus nevus had an accuracy of 87.3% [95% confidence interval (CI), 81.1-92.1], a sensitivity of 77.9% (95% CI, 68.9-85.4), a specificity of 98.6% (95% CI, 95.8-100), a positive predictive value of 98.5% (95% CI, 95.6-100), and a negative predictive value of 78.9% (95% CI, 72.6-85.4).
In addition, we show that skin DNA methylation is associated in cis with known genome-wide association study single nucleotide polymorphisms for nevus count, at PLA2G6 (P = 1.7 × 10<sup>-49</sup>) and NID1 (P = 6.4 × 10<sup>-14</sup>), as well as melanoma risk, including in or near MC1R, MX2, and TERT/CLPTM1L (P < 1 × 10<sup>-10</sup>).