Noninvasive Analysis of High-Risk Driver Mutations and Gene Expression Profiles in Primary Cutaneous Melanoma

Tools that help reduce the number of surgical biopsies performed on benign lesions have the potential to improve patient care. The pigmented lesion assay (PLA) is a noninvasive tool validated against histopathology that helps rule out melanoma and the need for surgical biopsies of atypical pigmented skin lesions. Genetic information is collected using adhesive patches and the expression of two genes, LINC and PRAME, is measured. By using genetic material collected noninvasively and to further validate the PLA, somatic hotspot mutations in genes known to be drivers of early melanoma development (BRAF other than V600E, NRAS, and the TERT promoter) can also be identified. The frequency of these hotspot mutations in samples of early melanoma was 77%, which is higher than the 14% found in nonmelanoma samples (P < 0.0001). TERT promoter mutations were the most prevalent mutation type in PLA-positive melanomas; 82% of PLA-negative lesions had no mutations, and 97% of histopathologically confirmed melanomas were PLA and/or mutation positive (cohort 1, n = 103). Mutation frequencies were similar in prospectively collected real-world PLA samples (cohort 2, n = 519), in which 88% of PLA-negative samples had no mutations. Combining gene expression and mutation analyses enhances the ability to noninvasively detect early cutaneous melanoma.