The investigators hypothesize that ctDNA levels drawn before and after surgical resection of a primary tumor and either sentinel lymph nodes or clinically involved metastatic lymph nodes will correlate with the presence of sentinel node microscopic metastatic disease and clinically evident nodal metastatic disease. The investigators also predict that approximately 20% of sentinel lymph node negative Stage IIB/IIC patients will have evidence of ctDNA positivity post-surgery.~Primary Objective:~To assess the feasibility of generating patient specific ctDNA assay from Signatera© test for primary melanoma samples submitted with clinical stage IIB/IIC and stage III melanoma patients.~Secondary Objective(s):~To investigate serum levels of melanoma ctDNA pre and postoperatively in clinical Stage IIB/C and Stage III melanoma patients.~To evaluate the relationship of serum ctDNA levels pre-operatively with sentinel lymph node biopsy status in clinical Stage IIB/C patients.~Evaluate for clearance or persistence of ctDNA levels post complete resection in patients with clinically evident lymph node metastasis (Stage IIIB/C/D).~Assess feasibility of collection of pre- and post-operative stool samples
This is a non-randomized experimental biomarker study evaluating ctDNA levels in patients with stage IIB/C and stage IIIB/C/D melanoma skin cancer pre and post-surgery~Study participants will complete a ctDNA test within 4 weeks of their planned surgical resection of their melanoma. Within 4 weeks post-surgery another ctDNA test will be completed. During these time points stool samples and diet questionnaires will be collected for biospecimen banking.