MERLIN_001 is a prospective registry study of a primary melanoma gene-signature to predict sentinel node (SN) status and to determine its prognostic value for more accurate staging of SN-negative melanoma patients.

Inclusion Criteria:

• Newly diagnosed patients with invasive malignant melanoma of the skin (AJCC 8th edition staging guidelines) elected to undergo sentinel lymph node biopsy per the treating physician's recommendation.
• Male or female, age ≥18 years.

Exclusion Criteria:

• Full primary melanoma pathology report unavailable.
• Documented clinically apparent nodal metastases at diagnosis.
• Distant metastatic disease (M1a,b,c,d) clinically present at primary diagnosis
• Any prior or concurrent primary invasive melanoma mapping to the same draining lymph node basin(s).
• Documented history of another (prior or concurrent) primary invasive melanoma of T1b or greater at any site within the last 5 years.
• Previous surgery in or radiation therapy to the draining lymph node basin(s) of the current primary melanoma.
• Ocular, vulvar, perianal or mucosal melanomas or melanocytic tumors of uncertain malignant potential (MELTUMP) or atypical Spitz tumors.

Prospectively collected primary cutaneous melanoma patients who are elected per treating physician's recommendation to undergo sentinel lymph node biopsy.