SkylineDx received FDA Breakthrough Device designation for Merlin CP-GEP, a clinicopathologic gene expression profiling assay intended to support risk assessment in early-stage cutaneous melanoma. The test stratifies patients into high- or low-risk categories to inform sentinel lymph node biopsy decisions and follow-up planning. The designation was supported by data from the MERLIN_001 trial, described as a large prospective multicenter blinded study. The assay is also recognized in National Comprehensive Cancer Network clinical practice guidelines as a predictive gene expression profiling test that can support decision-making in T1b and T2a melanoma patients. For developers of companion diagnostics, the Breakthrough designation highlights FDA’s continued willingness to treat solid-tumor molecular risk tools as decision-support devices, not only as retrospective prognostic markers.