Utility of a 31-gene expression profile for predicting outcomes in patients with primary cutaneous melanoma referred for sentinel node biopsy

Background: A 31-gene genetic expression profile (31-GEP; Class 1 = low risk, Class 2 = high risk) developed to predict outcome in cutaneous melanoma (CM) has been validated by retrospective, industry-sponsored, or small series. Methods: Tumor features, sentinel node biopsy (SNB) results, and outcomes were extracted from a prospective database of 383 C M patients who underwent SNB and had a 31-GEP run on their primary tumor. Groups were compared by uni- and multi-variable analysis. Relapse-free and distant metastasis-free survival (RFS, DMFS) were estimated by Kaplan-Meier method. Results: Breslow thickness, T stage, and SNB positivity were significantly higher in Class 2 patients. Recurrence rates were higher for Class 2 vs Class 1 patients and highest in patients who were Class 2 and SNB positive. GEP class was predictive of RFS and DMFS and independently predicted relapse in AJCC “low risk” (stages IA-IIA) patients. Conclusions: 31-GEP adds prognostic information in CM patents undergoing SNB.