Abstract
Purpose:
To compare gene expression profiling (GEP) using DecisionDX-UM® with multiplex ligation-dependent probe amplification (MLPA) in molecular typing and predicting metastatic risk of choroidal melanomas (CM).
Methods:
20 enucleated formalin-fixed, paraffin-embedded (FFPE) CM, previously examined by DecisionDX-UM®, were tested with MLPA, and then categorized with both methods independently in a masked manner as having “minimal”, “low” or “high” metastatic potential. Results were correlated with clinical and histologic metastasis predictors, and the 10-year risk of metastatic death was estimated by multivariate analysis using Liverpool Uveal Melanoma Prognosticator Online (LUMPO).
Results:
The patients’ median age was 60 years, and the CM a median largest basal diameter and height of 18.4 mm and 10.2 mm. The TNM stages of the CM were: IIA (n=2), IIB (3), IIIA (3) IIIB (9) and IIIC (3). DecisionDX-UM® classified the CM as Class 1A (n=4), Class 1B (n=7) and Class 2 (n=9). MLPA indicated “minimal”, “low” and “high” risk in 4, 5 and 11 patients, respectively. Discordant results occurred in 5 CM (25%; 95% confidence interval, 9-49), with MLPA indicating a higher risk of metastasis in 3 and DecisionDX-UM® in 2. Associations with clinical and histomorphologic metastasis predictors were similar. Multivariate LUMPO predictions of the 10-year metastatic mortality for all patients had medians of 37% and 41% according to DecisionDX-UM® and MLPA results, respectively. Four patients with "high" risk had succumbed to their disease; all of the UM patients with "minimal" or "low" risk were still alive at time of abstract submission.
Conclusions:
DecisionDX-UM® and MLPA in FFPE agreed well with each other, with metastasis predictors and with survival estimates. For most CM patients both methods are likely to provide similar results in clinical use.
Keywords: 452 choroid •
589 melanoma •
539 genetics