Serum gp100 as an Independent Prognostic Biomarker in Early-Stage Uveal Melanoma.

Purpose: To evaluate the prognostic significance of serum gp100 levels in patients with uveal melanoma (UM) without detectable metastases at diagnosis. Methods: This prospective study included 37 patients with UM and no clinical evidence of metastasis at baseline. Serum gp100 concentration was quantified using a commercial ELISA kit. Tumors were molecularly profiled and categorized into high- or low-risk classes. Patients were stratified based on the median gp100 concentration (1.23 ng/mL). Survival analysis was performed using Kaplan-Meier estimates, and multivariate logistic regression was used to identify independent predictors of metastasis. Results: During a mean follow-up of 24.6 months, 14 patients (37.8%) developed metastases. Patients with baseline gp100 >1.23 ng/mL had significantly shorter metastasis-free survival (P < 0.001). Receiver operating characteristic (ROC) analysis yielded an area under the curve of 0.89, with a cutoff of 1.387 ng/mL, achieving 85.7% sensitivity and 82.6% specificity. In multivariate analysis, serum gp100 remained an independent predictor of metastasis (odds ratio = 3849.9; 95% confidence interval, 9.66-1,534,206; P = 0.007), regardless of molecular classification. No significant correlations were found between gp100 and clinical or genetic parameters. Conclusions: Elevated serum gp100 is an independent biomarker of early metastatic risk in UM, even in the absence of clinical or genetic high-risk features. ELISA-based measurement of gp100 may support noninvasive stratification and personalized surveillance strategies in clinical practice.