Gene expression profiling for molecular staging of cutaneous melanoma in patients undergoing sentinel lymph node biopsy

Background: A gene expression profile (GEP) test able to accurately identify risk of metastasis for patients with cutaneous melanoma has been clinically validated. Objective: We aimed for assessment of the prognostic accuracy of GEP and sentinel lymph node biopsy (SLNB) tests, independently and in combination, in a multicenter cohort of 217 patients. Methods: Reverse transcription polymerase chain reaction (RT-PCR) was performed to assess the expression of 31 genes from primary melanoma tumors, and SLNB outcome was determined from clinical data. Prognostic accuracy of each test was determined using Kaplan-Meier and Cox regression analysis of disease-free, distant metastasis-free, and overall survivals. Results: GEP outcome was a more significant and better predictor of each end point in univariate and multivariate regression analysis, compared with SLNB (P < .0001 for all). In combination with SLNB, GEP improved prognostication. For patients with a GEP high-risk outcome and a negative SLNB result, Kaplan-Meier 5-year disease-free, distant metastasis-free, and overall survivals were 35%, 49%, and 54%, respectively. Limitations: Within the SLNB-negative cohort of patients, overall risk of metastatic events was higher (similar to 30%) than commonly found in the general population of patients with melanoma. Conclusions: In this study cohort, GEP was an objective tool that accurately predicted metastatic risk in SLNB-eligible patients.